[1] After graduating, he went to Marquette University in Milwaukee, Wisconsin, and played his first football game for the college team in 1941, when he was a sophomore.

[1] Harrington then entered the Second Air Force during World War II and was the captain of the unit's Superbombers football team, who played in the Treasury Bond Bowl in 1944.

In March 1946, the Cleveland Browns of the new All-America Football Conference (AAFC) announced that they had signed Harrington.

[6] He reported to the team's training camp several days late to finish summer school studies at Marquette, to which he had returned after his discharge from the Army.

[8] Before the 1947 season began, the Browns traded Harrington and Jim Daniell to the AAFC's Chicago Rockets for halfback Bill Boedeker.