Leadership Team

Brian X. Tierney

President and Chief Executive Officer
FirstEnergy Corp. 

Brian Tierney joined FirstEnergy in June 2023 as president and chief executive officer. He is also a member of the board of directors.

Previously, Tierney was a senior managing director and global head of Infrastructure Operations and Asset Management at Blackstone.

Prior to joining Blackstone in 2021, Tierney spent more than 23 years at American Electric Power (AEP), one of the largest electrical utilities in the United States. He held a number of senior leadership positions at AEP, including executive vice president of Strategy and more than 11 years as executive vice president and chief financial officer. As CFO, Tierney directed the company’s finance and accounting activities and also had responsibility for strategy, procurement, supply chain and fleet operations. Tierney gained operations experience as executive vice president – AEP Utilities East, AEP’s largest regulated utility region, responsible for the distribution, customer service and financial performance of AEP’s utility operating companies in the states of Indiana, Kentucky, Michigan, Ohio, Tennessee, Virginia and West Virginia. 

Michelle Henry

Senior Vice President, Customer Experience
FirstEnergy Service Company

Michelle Henry leads FirstEnergy’s customer service function and its sales, products and services, and energy efficiency initiatives.

Henry began her career with the Cleveland Electric Illuminating Company in 1988 as a Scholastics Awards Student engineer at the Perry Nuclear Power Plant. She has served as the manager, Business Analytics; manager, Corporate Cash Management; and manager, Finance Strategy and Reporting. She became manager, FERC and Transmission Technical Support for FirstEnergy Utilities in 2011 and was promoted to director, Market Policy for FirstEnergy Service Company in 2014. She served as director, FERC & State Regulatory Compliance before being named vice president of Customer Service for FirstEnergy Utilities, a subsidiary of FirstEnergy Corp., in May 2020. She was promoted to her current position effective August 2021.

Mark D. Mroczynski

Acting Vice President, Operations 

Mark Mroczynski is acting vice president, Operations.

He joined FirstEnergy in 2004 as supervisor of Technical Services for the Bruce Mansfield Power Plant and became manager of Technical Services for Consolidated Coal Plants in 2006. He was named director, Operations Support for Ohio Edison and Penn Power in 2008 and became executive director, Transmission Programs in 2013. He was promoted to vice president, Construction and Design Services in 2018 and named to his current position in May 2023.

Prior to joining FirstEnergy, Mroczynski spent 18 years with J&L Specialty Steel, serving in a number of operations management and supply chain positions.

Hyun Park     

Senior Vice President and Chief Legal Officer
FirstEnergy Service Company

Hyun Park joined FirstEnergy in 2021 as senior vice president and chief legal officer for FirstEnergy. He is responsible for the company's legal and internal audit functions, and oversees the company’s ethics and compliance program. 

Previously, Park was partner and general counsel of LimNexus LLP, where he advised clients on a wide variety of complex matters, including crisis management, litigation and corporate transactions. Prior to joining LimNexus in October 2019, he was Of Counsel at Latham & Watkins LLP. From 2006 to 2017, Park served as senior vice president and general counsel for PG&E Corporation and its businesses, including its principal subsidiary, Pacific Gas and Electric Company. Prior to joining PG&E Corporation, he was vice president, general counsel and secretary of Allegheny Energy, Inc. and previously served as senior vice president, general counsel and secretary of Sithe Energies, Inc. He began his career at Latham & Watkins and became an equity partner there. 

K. Jon Taylor 

Senior Vice President, Chief Financial Officer and Strategy
FirstEnergy Service Company

Jon Taylor is senior vice president, chief financial officer and strategy for FirstEnergy, with responsibility for accounting; treasury; investor relations and communications; risk; supply chain; and rates and regulatory affairs. 

Taylor joined FirstEnergy in 2009 from PricewaterhouseCoopers, LLP. He progressed through various senior level financial positions, including assistant controller FirstEnergy Utilities and assistant controller FirstEnergy Solutions and FirstEnergy Generation. In October 2012, he was promoted to vice president and assistant controller for FirstEnergy Corp., and he was named vice president, controller and chief accounting officer in 2013. In March 2018, Taylor was named president of Ohio Operations, then he was promoted to vice president, FirstEnergy Utilities in April 2019. He was elected senior vice president and chief financial officer in May 2020 and named to his current position effective August 2021.

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Christine L. Walker

Senior Vice President, 
Chief Human Resources Officer and Corporate Services
FirstEnergy Service Company

Chris Walker leads FirstEnergy's human resources and corporate services functions. She has responsibility for talent management; total rewards; diversity, equity and inclusion; labor relations and safety; flight operations; real estate and facilities services. 

Walker began her career with GPU, Inc., in the Information Technology organization and held various positions in Human Resources and Customer Service prior to GPU's merger with FirstEnergy in 2001. She was promoted to director, Compensation and Retirement programs in 2005, executive director, Human Resources, in 2011, and executive director, Talent Management, in 2016. She was named vice president, Human Resources, in 2018 and was promoted to senior vice president and chief human resources officer in May 2019. She was named to her current position effective August 2021.

Antonio Fernández

Vice President and Chief Ethics and Compliance Officer
FirstEnergy Service Company    

As chief ethics and compliance officer, Antonio Fernández leads a dedicated team of compliance professionals with a focus on strengthening the company's ethics and compliance function. He reports to the senior vice president and chief legal officer as well as the Audit Committee of the Board, and collaborates closely with the compliance oversight subcommittee of the Audit Committee.

Fernández joined FirstEnergy in April 2021 after five years as chief compliance, NERC & privacy officer of Public Service Enterprise Group (PSEG), where he led PSEG’s ethics, compliance and privacy programs, advised senior management and the Board of Directors on the company’s compliance program and provided advice on ethics, compliance, privacy and cybersecurity matters. Before joining PSEG in 2016, he was global ombuds leader and executive counsel for GE Power. During his five years at GE, he held various roles of increasing responsibility in GE’s compliance program, including serving as chief compliance officer for GE’s nuclear business and as GE’s corporate ombuds leader. Earlier in his career, Fernández was a senior attorney for Florida Power & Light from 2007 to 2011 and nuclear counsel for Pacific Gas and Electric Company from 2005 to 2007. He began his career at the United States Nuclear Regulatory Commission Office of the General Counsel in its Honors Program.

Irene M. Prezelj

Vice President, Investor Relations & Communications
FirstEnergy Service Company    

Irene Prezelj is responsible for managing the company's relationships with the investment community, communications and branding, and corporate responsibility.

Prezelj joined the company in 1984, and progressed through positions in the Marketing, Public Affairs and Market Intelligence departments. She became manager, Investor Relations, in 2008, then was promoted to director, Investor Relations, in 2009 and to executive director, Investor Relations, in 2011. She was named vice president, Investor Relations in 2011, and was promoted to her current role effective August 2021.