Following his collegiate playing career, Harrington was invited to try out for the 1979–80 US National team coached by the Minnesota Golden Gophers' Herb Brooks.

The team went on to defeat the highly favored Soviet Union 4–3 in the first game of the Medal Round in an event named the "Miracle on Ice".

The Sabres immediately assigned him to the Rochester Americans of the AHL, where he scored seven points in twelve games despite being a marked man.

"Some Canadian-born kids resent the fact that the Americans did so well in the Olympics and they're a bit jealous of them," claimed Buffalo defenseman Larry Playfair.

In one game Harrington was struck in the face and needed six stitches to close a bloody gash on his chin.

In another game against the Hershey Bears Harrington was attacked from behind by Lou Franceschetti and knocked unconscious for five minutes, lying in a pool of blood on the ice.

He had to spend the night in a hospital with a concussion, fractured jaw, broken nose and four loosened teeth.

Following 1984, Harrington retired from playing and rejoined his college roots as an assistant coach under former Montreal Canadiens star Ralph Backstrom at the University of Denver.

[2] On January 19, 2009 Harrington signed a contract as head coach for Slovenia men's national ice hockey team,[3] a position he held until December 12, 2010 when he was succeeded by Matjaž Kopitar.

Among family, friends and those who knew him in his high school and college playing days, Harrington is known almost exclusively as "Bah".