updated 3:27 p.m. ET March 17, 2009

WASHINGTON - President Barack Obama on Tuesday selected Pittsburgh Steelers owner Dan Rooney to be U.S. ambassador to Ireland, turning to a lifelong Republican who provided the Democrat critical campaign support during the White House race.

The 76-year-old Rooney endorsed Obama over Hillary Rodham Clinton during Pennsylvania’s contentious Democratic primary; Clinton won the contest last April. Rooney later campaigned for him in Steelers country in western Pennsylvania, and Obama went on to win the state last November.

The grandson of an Irish immigrant, Rooney in the 1970s helped found the American Ireland Fund, an organization that has raised millions for advocacy of peace and education in Ireland. His legacy is reflected in a Steelers-themed bar in a disused linen mill in one of the roughest parts of northwest Belfast.

In announcing the nomination on St. Patrick’s Day, Obama called Rooney “an unwavering supporter of Irish peace, culture and education.”

Obama said in a statement that he has confidence that Rooney and Secretary of State Clinton “will ensure America’s continued close and unique partnership with Ireland in the years ahead.”

Rooney’s father, Arthur J. Rooney, founded the Steelers in 1933. The son took over the presidency of the team in 1975 and is a Hall of Fame owner. His Steelers won the Super Bowl this year, shocking the Arizona Cardinals 27-23 on Santonio Holmes’ tiptoe catch for a touchdown with 35 seconds to play.

The “Rooney Rule,” which requires any team with a head coaching vacancy to interview at least one minority candidate, was developed by an NFL committee Rooney chaired. Rooney has also participated in labor negotiations between the league and players.

Dan Rooney’s son, Art Rooney II, who took over as team president in 2003, said he was happy for his father. In a statement, Art Rooney said the Steeler operation will continue as they have in the past with the goal of winning another Super Bowl.

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