Barr attended the University of Southern California (USC), where his teammates included Dave Kingman, and helped lead their baseball team to a pair of NCAA championships in 1968 and 1970.

He joined the team's rotation in the middle of 1972 and, despite never pitching a no-hitter or perfect game, that summer set the record for consecutive batters retired.

On August 23 against the Pittsburgh Pirates, he walked opposing pitcher Bob Moose to lead off the third inning and then retired the final 21 batters to end the game with a 2-hitter.

However, Barr did not pitch for the Angels in the playoffs after breaking his hand punching a toilet at a party celebrating their division championship.

Additionally, his brother, Mark Barr, pitched in the Boston Red Sox farm system for several years in the 1970s.