Board of Directors

Director since 2017

Mr. Hennigan is executive chairman of the board of MPLX GP LLC. He is also executive chairman of the board of Marathon Petroleum Corporation.

Mr. Hennigan served as the chairman, president and chief executive officer of MPLX GP LLC and chief executive officer of Marathon Petroleum Corporation until August 2024, when he transitioned to executive chairman. Prior to joining MPLX GP LLC in 2017, Mr. Hennigan was president, crude, NGL and refined products of the general partner of Energy Transfer Partners L.P.  Prior to that, he served as president and chief executive officer of Sunoco Logistics Partners L.P. He was responsible for all operations and business activities, including setting the direction, strategy and vision for the company. 

Mr. Hennigan began his career with Sunoco, Inc. in 1981 at the Marcus Hook refinery, working in various engineering and operations positions before joining the business planning department in 1990. In 1992, he transferred to the Philadelphia refinery before joining the corporate business planning group in 1993. There, he worked on various strategies for northeast refining before returning to Marcus Hook as business manager in 1996. In 1998, he returned to Sunoco’s corporate office as manager, financial analysis and strategic planning. In 2000, he was named general manager, northeast refining wholesale fuels marketing and product supply and in 2001 was appointed vice president, product trading, sales and supply. In 2006, Mr. Hennigan was appointed senior vice president, supply, trading, sales and transportation and senior vice president, business improvement in 2008. Mr. Hennigan joined Sunoco Logistics as vice president, business development in 2009. He was named president and chief operating officer in 2010 and was appointed as president and chief executive officer in 2012. In 2017, Mr. Hennigan was named president of MPLX GP LLC and in 2019 was named president and chief executive officer.  In 2020, he was named president and chief executive officer of Marathon Petroleum Corporation and in 2024, Mr. Hennigan served exclusively as the chief executive officer. 

Mr. Hennigan holds a Bachelor of Science degree in chemical engineering from Drexel University.

Mr. Hennigan serves on the boards of directors of Marathon Petroleum Corporation and Nutrien Ltd.

Director since 2012

Mr. Helms is president and chief executive officer of US Shale Management Company, a wholly owned subsidiary of U.S. Shale Energy Advisors LLC.

Mr. Helms is the co-founder of U.S. Shale Energy Advisors LLC, a privately-owned entity engaged in the development, ownership and operation of midstream energy assets. Through subsidiaries it owns and operates Rocky Mountain Crude Oil LLC, a crude oil logistics company focused on the transportation of crude oil produced in North Dakota, Colorado, Montana, Wyoming, Nebraska, Utah, Texas and New Mexico. From 2005 until his retirement in 2011, Mr. Helms served in various capacities with NiSource Inc. and its affiliate, NiSource Gas Transmission and Storage, including as executive vice president and group chief executive officer. He was group president, pipeline of NiSource Inc. from 2005 to 2008, where he was also a member of the Executive Council and the Corporate Risk Management Committee. He served as chief executive officer and executive director of NiSource Gas Transmission and Storage from 2008 to 2011. At NiSource, Mr. Helms was responsible for leading the company’s interstate gas transmission, storage and midstream businesses. Prior to his tenure at NiSource, Mr. Helms held senior executive positions with CMS Energy Inc., and subsidiaries of Duke Energy Corporation and Pan Energy Inc. from 1990-2005.

Mr. Helms graduated with a Bachelor of Arts degree from Southern Illinois University at Edwardsville and a juris doctor degree from the Tulane University School of Law.

Director since 2022

Ms. Breves most recently was executive vice president, Business Transformation at United States Steel Corporation. Prior to that role, she was senior vice president and chief financial officer for United States Steel Corporation from 2019 through August 2022.

Ms. Breves began her career with Alumax Inc., where she held positions in accounting, maintenance and procurement. In 1998, Alumax Inc. was acquired by Alcoa, where she served in various leadership positions, including chief procurement officer. In 2013, Ms. Breves joined United States Steel Corporation as vice president and chief procurement officer. She held several positions of increasing responsibility, including senior vice president, manufacturing support and chief supply chain officer before serving as senior vice president and chief financial officer from 2019 until August 2022 when she transitioned into the role of executive vice president, Business Transformation until her retirement from Unites States Steel in December 2022. 

Ms. Breves graduated with a bachelor’s degree in business administration from the College of Charleston and a master’s degree in business administration from The Citadel. 

Ms. Breves received the Wall Street Journal Award given annually by the College of Charleston to the top business and economics graduate. Ms. Breves also received the 2007 Alumni of the Year Award from the College of Charleston School of Business and Economics. She received the 2018 Shipman Medal given annually by the Institute of Supply Management. Ms. Breves is a past chairperson of CAPS Research Advisory Board and is a past member of the national Board of Directors of the Institute for Supply Management. In addition to serving on the MPLX board of directors, Ms. Breves is a member of the boards of directors of Sylvamo Corporation and RXO Corporation.

Mr. Hagedorn is executive vice president and chief financial officer of MPLX GP LLC.

Mr. Hagedorn joined MPLX GP LLC in 2017 as vice president and controller. In 2021, he was named senior vice president and controller of Marathon Petroleum Corporation. Prior to joining MPLX GP LLC, Mr. Hagedorn was vice president and controller at CONSOL Energy Inc. He was a key member of the leadership team that prepared for the formation and initial public offering of a midstream master limited partnership formed by CONSOL Energy and served as the partnership's chief accounting officer. Mr. Hagedorn joined CONSOL in 2012 as director, financial accounting and was named assistant controller in 2014, and vice president and controller in 2015. He served as chief accounting officer for CONE Midstream Partners LP from 2014 to 2015. Mr. Hagedorn joined PricewaterhouseCoopers in 1998. During his 14-year career with PwC, he held the positions of audit associate, audit senior associate, audit manager and audit senior manager. Mr. Hagedorn assumed his current position in 2024.

Mr. Hagedorn earned a bachelor’s degree in accounting from West Virginia University. He is a licensed certified public accountant in Pennsylvania.

Director since 2021

Ms. Mannen is president and chief executive officer of MPLX GP LLC. She is also president and chief executive officer of Marathon Petroleum Corporation. 

Ms. Mannen was named president of Marathon Petroleum Corporation in January 2024 and assumed her current role in August 2024. Previously, she served as executive vice president and chief financial officer of Marathon Petroleum Corporation since 2021.

Prior to joining Marathon Petroleum Corporation in 2021, Ms. Mannen served as executive vice president and chief financial officer of TechnipFMC, a leading global engineering services and energy technology company incorporated in the United Kingdom and headquartered in Paris and Houston. From 2011 to 2017, she was chief financial officer at FMC Technologies, prior to its merger with Technip SA, which Ms. Mannen played a key role in negotiating and executing. Before that, she served as the company's deputy chief financial officer and treasurer from 2010 to 2011 and vice president of administration from 2007 to 2010. Prior to joining FMC Technologies in 1986, Ms. Mannen was finance manager for Sheller-Globe Corporation.

Ms. Mannen holds a bachelor's degree in accounting and a Master of Business Administration degree from Rider University.

Ms. Mannen serves on the board of directors of Marathon Petroleum Corporation. She is a member of the Owens Corning board of directors, where she has served as the audit committee chair since 2019. Ms. Mannen also serves on the executive committee of the American Petroleum Institute (API), the executive committee of American Fuel and Petrochemical Manufacturers (AFPM), and the executive committee of the Ohio Business Roundtable, and is a member of The Business Council. She also serves as secretary of the Cynthia Woods Mitchell Pavilion board of directors and is a member of its executive and finance committees.

Director since 2012

Mr. Peiffer is the retired president of MPLX GP LLC and retired executive vice president, Corporate Planning and Investor and Government Relations of Marathon Petroleum Corporation. 

Mr. Peiffer began his career with Marathon in 1974 as an internal auditor. During his career, he held a variety of management positions with increasing responsibilities. These responsibilities included supervisor of employee savings and retirement plans, controller of Speedway Petroleum Corporation and numerous other marketing and logistics positions. In 1987, Mr. Peiffer was appointed to the President's Commission on Executive Exchange serving for a year in the Pentagon as special assistant to the Assistant Secretary of Defense for Production and Logistics. In 1988, he returned to Marathon Oil and was named vice president of Finance and Administration for Emro Marketing Company. He served as assistant controller, Refining, Marketing and Transportation beginning in 1992. Mr. Peiffer was named senior vice president of Finance and Commercial Services for Marathon Ashland Petroleum LLC¹ in 1998, executive vice president of Marathon Petroleum Corporation in 2011 and president of MPLX GP LLC in 2012 until his retirement in 2014.

Mr. Peiffer graduated with a bachelor’s degree in accounting from Bowling Green State University in 1974 and passed the certified public accountant exam in Ohio that same year.

Mr. Peiffer is a member of the Findlay-Hancock County Community Foundation’s Finance & Investment and Audit committees and serves on the boards of Blanchard Valley Port Authority and Catholic Community Foundation-Ohio.

Mr. Quaid is executive vice president and chief financial officer of Marathon Petroleum Corporation.

Prior to joining Marathon Petroleum Corporation in 2014, Mr. Quaid served as vice president of iron ore for U.S. Steel, where he had responsibility for all aspects of iron ore mining operations. While at U.S. Steel, Mr. Quaid also served as vice president and treasurer where he had executive responsibility for all of U.S. Steel's treasury functions, including capital markets, corporate finance, cash and banking, credit and collections and insurance. He also served as a member of the United States Steel and Carnegie Pension Fund’s investment committee.

Mr. Quaid began his career at PricewaterhouseCoopers LLP (PwC) in the audit and assurance practice and was promoted to manager in 1998. While at PwC, he served a number of major companies in the steel, oil and gas, networking technology and consumer products industries. In 2000, he joined FastForward Inc., an enterprise marketing software developer and service provider startup company as corporate controller. In 2002, Mr. Quaid joined U.S. Steel as manager of Investor Relations. In 2004, he advanced to director of Facility Marketing and Business Planning and was responsible for sales and operations planning activities. In 2005, he relocated to Serbia after being named director of Finance for the former U.S. Steel Serbia with responsibility for accounting, financial planning and analysis, tax, and treasury. Mr. Quaid returned to the U.S. in 2007, to serve as a lead project manager for U.S. Steel's enterprise resource planning project. He advanced to assistant corporate controller in 2008, and was named controller, North American Flat-Rolled Operations in 2010. Mr. Quaid was elected vice president and treasurer in August 2011, and assumed the role of vice president iron ore at U.S. Steel in 2014. He was named senior vice president and controller of Marathon Petroleum Corporation in 2014. He was named executive vice president and chief financial officer of MPLX GP LLC in 2021. Mr. Quaid assumed his current position in 2024.

Mr. Quaid graduated from Lehigh University in 1994, with a Bachelor of Science business and economics degree in accounting.

Director since 2015

Mr. Semple is the retired chairman, president and chief executive officer of MarkWest Energy Partners, L.P. 

Mr. Semple joined MPLX in 2015, at the time of the MPLX and MarkWest combination and retired in 2016. He joined MarkWest in 2003, as president and chief executive officer and was elected chairman of the board in 2008. Prior to joining MarkWest, Mr. Semple completed a 22-year career with The Williams Companies and WilTel Communications. He served as the chief operating officer of WilTel Communications, senior vice president/general manager of Williams Natural Gas Company, vice president, operations and engineering for Northwest Pipeline Company and division manager for Williams Pipeline Company. Prior to his time at The Williams Companies, Mr. Semple served in the U.S. Navy.

Mr. Semple earned a bachelor’s degree in mechanical engineering from the United States Naval Academy. He completed the Program for Management Development at Harvard Business School.

Mr. Semple serves on the boards of directors of Marathon Petroleum Corporation, Choctaw Global, LLC, an affiliate of the Choctaw Nation of Oklahoma, National Cowboy & Western Heritage Museum and the Semple Family Museum of Native American Art.

Director since 2018

Mr. Stice is a professor at the University of Oklahoma and previously served as the Dean, Mewbourne College of Earth & Energy, the University of Oklahoma.

Mr. Stice began his career in 1981 with Conoco, as an associate engineer. He held engineering positions of increasing responsibility prior to being named plant manager of Louisiana Gas System Inc. in 1987. In 1991, Mr. Stice was named district manager for the Oklahoma district. He was appointed managing director of Conoco Australia Pty. Ltd. in 1995 and president, Conoco Asia Pacific Ltd. in 1997. Mr. Stice was promoted to president of Conoco Energy Solutions in 2001 and president of ConocoPhillips Qatar in 2003. In 2008, Mr. Stice was named president and chief operating officer of Chesapeake Midstream Development, L.P., a wholly owned subsidiary of Chesapeake Energy Corporation, and senior vice president of natural gas projects for Chesapeake. In 2009, he was named chief executive officer of Chesapeake Midstream Partners, L.P. Mr. Stice was designated a director of Chesapeake Midstream Partners, which changed its name to Access Midstream in 2012. He continued as chief executive officer until his retirement in 2014. Mr. Stice served as Dean, Mewbourne College of Earth and Energy at the University of Oklahoma since August 2015 and assumed his current position in January 2023.

Mr. Stice holds a bachelor’s degree in chemical engineering from the University of Oklahoma, a master’s degree in business from Stanford University, and a doctorate in education from The George Washington University.

Mr. Stice serves on the boards of directors of Marathon Petroleum Corporation and Kosmos Energy Ltd. He previously served on the boards of directors of MarkWest Energy Partners, L.P. and Spartan Acquisition III Corp.

Director since 2012

Mr. Surma is the lead director of the board of Marathon Petroleum Corporation.  He is also the retired chairman and chief executive officer of United States Steel Corporation.

Mr. Surma began his career at Price Waterhouse LLP where he was admitted to the partnership in 1987. In 1983, Mr. Surma participated in the President’s Executive Exchange Program in Washington, D.C., where he served as executive staff assistant to the vice chairman of the Federal Reserve Board. Mr. Surma joined Marathon in 1997, where he served in several executive positions. He was named senior vice president, Finance and Accounting of Marathon Oil Company in 1997, president, Speedway SuperAmerica LLC in 1998, senior vice president, Supply and Transportation of Marathon Ashland Petroleum LLC in 2000, and president of Marathon Ashland Petroleum LLC in 2001. Mr. Surma joined United States Steel at the time of its separation from Marathon. He retired as the chief executive officer of United States Steel Corporation in September 2013 and as executive chairman in December 2013.

Mr. Surma earned a Bachelor of Science degree in accounting from Pennsylvania State University in 1976.

Mr. Surma is a member of the boards of directors of Public Service Enterprise Group Incorporated (PSEG) and Trane Technologies plc. He is also the chair of the board of directors of the University of Pittsburgh Medical Center. Mr. Surma formerly served as the chair of the board of directors of the Federal Reserve Bank of Cleveland and the National Safety Council. He was appointed by President Barack Obama to the President's Advisory Committee for Trade Policy and Negotiations and served as its vice chairman.