Senior Management

Carl H. Lindner III was elected Co-Chief Executive Officer in January 2005. He has served as Co-President and a director of American Financial Group since March 1996. He has been principally responsible for the Company's property and casualty insurance operations since 1987. He became involved in Great American’s property and casualty business in 1975 and has worked in varying roles of increasing responsibility over the years.

John B. Berding was elected President of American Financial Group in June 2023. Since 2011 he has also served as President of American Money Management Corporation (AMMC), AFG’s subsidiary providing investment management services to AFG, its insurance subsidiaries and certain third-party investment entities. Prior to his election as President of AMMC, he held a number of investment-related executive positions with AMMC and other AFG subsidiaries. Mr. Berding has over 35 years of experience as an investment professional. 

Michelle A. Gillis was appointed Chief Human Resources Officer in 2022 and elected Senior Vice President of the Company in March 2013. Since March 2012, she served as Vice President and Chief Administrative Officer of the Company with responsibilities for Human Resources, Corporate Communications, Real Estate and various shared service areas. Prior to this role, she served as Vice President overseeing Human Resources. Since joining Great American Insurance Company in 2004, Ms. Gillis held various senior human resource management positions. Previously, Ms. Gillis spent several years in senior human resources roles in the financial services sector.

Brian S. Hertzman was elected Senior Vice President and Chief Financial Officer of American Financial Group in August 2020. Prior to this role, he served as Vice President and Controller of AFG, with responsibility for oversight of accounting policies and procedures in compliance with GAAP and other applicable regulations, and financial reporting to the Securities and Exchange Commission. Since joining AFG in 1991, Mr. Hertzman has held positions of increasing responsibility within the Company’s finance and accounting areas during his over 30-year tenure. Mr. Hertzman is a Certified Public Accountant (CPA) in the State of Ohio (inactive), and a member of the American Institute of CPAs, the Ohio Society of CPAs and Financial Executives International.

Mark A. Weiss was elected Senior Vice President and General Counsel of American Financial Group in December 2022. He joined AFG in 2010 as Assistant Vice President and Assistant General Counsel. In 2015, he was promoted to Vice President, and he assumed the role of Chief Compliance Officer in 2020. Mr. Weiss spent several years in private practice as a corporate and transactional lawyer prior to joining the Company.