Mark L. Attanasio (born September 29, 1957 in The Bronx, NYC) is an American businessman who is the principal owner of the Milwaukee Brewers. In September 2004, he reached a deal, on behalf of an investment group, to purchase the Brewers from the family of Major League Baseball (MLB) commissioner Bud Selig for an estimated US$223 million. The deal was approved by MLB at the owners' winter meeting on January 13, 2005.

Mark was born in The Bronx, New York and grew up in Tenafly, New Jersey, where he attended high school. The name Attanasio is derived from the Greek Athanasius, which means “immortal.” In particular, that name is associated with Athanasius of Alexandria, a bishop who played an important role in shaping the Christian faith at a relatively early point in its existence, so much so that he is remembered as a saint.

He graduated from Brown University with a B.A. in 1979 and received his J.D. from Columbia Law School in 1982. He co-founded the Los Angeles investment firm Crescent Capital Group in 1991, which was later bought by Trust Company of the West in 1995.

In September 2004, the Milwaukee Brewers and the Selig family announced that they had accepted Attanasio's bid to buy the team. Along with Brewers Assistant General Manager Gord Ash and former pitcher Ben Sheets, Attanasio is also a part-owner of the American Hockey League's Milwaukee Admirals. He was a major sponsor of the widely acclaimed Andy Warhol exhibition at the Milwaukee Art Museum.

Mark holds positions on several not-for-profit boards, including the board of trustees of Heal the Bay, the Los Angeles County Museum of Art and Harvard-Westlake School. He is also a member of Major League Baseball's Executive Council and Revenue Sharing Definitions Committee, and is chairman of its Investment Committee. Additionally, he is a member of LA2028, the bid committee that successfully secured the 2028 Summer Olympic Games in Los Angeles.

Mark is the brother of television writer Paul Attanasio. He is married to Deborah (nee Kaplan) and has two sons, Dan and Mike. His eldest son Dan and his rock band, Pan Am, performed at Summerfest 2008 in Milwaukee, Wisconsin.

(excerpted from Baseball Almanac, BR Bullpen & Wikipedia)