John A. Catsimatidis (born September 7, 1948, in Athens, Greece) is an American billionaire businessman, radio talk show host, and political figure. He immigrated to the United States with his family at a young age, settling in New York City where he was raised in a working-class Greek immigrant household. Catsimatidis attended the New York University Tandon School of Engineering but dropped out after two years to pursue entrepreneurial opportunities, starting with a small oil refining business in the early 1970s. His early ventures laid the foundation for his expansive business empire, reflecting his self-made success from humble beginnings in the competitive New York real estate and retail sectors.

Catsimatidis is the owner, president, chairman, and CEO of the Red Apple Group, a conglomerate with approximately $2 billion in holdings spanning real estate, aviation, and energy sectors across New York, Florida, and Pennsylvania. He also owns and operates Red Apple Media, which includes WABC radio station in New York, where he hosts conservative talk shows and compensates figures like Mark Levin for their contributions. His business interests control major supermarket chains including Gristedes and D'Agostino in Manhattan, as well as the United Refining Company, a subsidiary focused on petroleum products. Known for his aggressive business tactics and philanthropy in Greek-American communities, Catsimatidis has built a reputation as an influential player in New York's economic landscape.

Politically active as a Republican, Catsimatidis has run unsuccessfully for mayor of New York City in 2013 and considered further bids, often aligning with conservative causes and supporting candidates through donations. His dual Greek-American heritage influences his advocacy for immigrant success stories and international business ties. Despite controversies over labor practices in his supermarkets and political endorsements, he remains a prominent voice in media and finance, leveraging his platforms to shape public discourse on economic and social issues.