LINCOLN, Neb. (AP) — Nebraska athletic director Tom Osborne is retiring as of Jan. 1.

The 75-year-old Osborne announced his decision Wednesday at a news conference. He says “the perception” that you’re getting old “can get in the way.” Osborne says he doesn’t want to be a distraction.

Osborne was one of the most successful football coaches in history. Every one of his 25 teams won at least nine games, and three of his last four teams won national championships. He retired with a career record of 255-49-3, an .836 winning percentage that ranked fifth all-time among Division I coaches, and 13 conference titles. He was inducted into the College Football Hall of Fame in 1998, the year after he retired.

After serving in Congress and losing a gubernatorial bid, he returned to the university in 2007 to take over the athletic department and oversee the rebuilding of the football program and shepherd the school’s move from the Big 12 to the Big Ten.

Under Osborne’s watch, the athletic department has built a new basketball practice facility and entered into a public-private partnership to build a 16,000-seat basketball arena in downtown Lincoln that will open for the 2013-14 season. He also oversaw an expansion project that will increase Memorial Stadium’s capacity to more than 90,000 next year.