After a collegiate career at Boston College culminating with his team captaincy in 1949, Spinney played nine professional seasons with the two iterations of the Baltimore Colts of the National Football League (NFL).

[1] After leaving Saugus High,[1] Spinney spent 1945 at Manlius Military Academy in DeWitt, New York, playing football for the school squad.

[4] Scouts for Louisiana State University called him "cagey" while a local beat sportwriter noted "he is never drawn in on end runs and he hustles every minute he is on the field, whether it be in practice or in a regular game.

[4] At the collegiate level, in an era which players frequently played both offensive and defensive sides of the ball under the single platoon system, Spinney was a stellar performer at end for the run-driven game.

Art Spinney, BC strong, silent type, is the perfect example of extraordinary defensive player and blocking dynamo, who typifies the coach's dream end.

Spinney's first game action in the green-and-silver uniform of the 1950 Colts came on Sunday, September 17, when the new Baltimore franchise suffered a 38–14 drubbing at the hands of Sammy Baugh and the Washington Redskins.

[11] Still feeling the effects of his brain injury on the Monday after his first regular season NFL game, Spinney opened his mail to be hit again, this time with notification to report for induction into the United States Army the following week at Lynn, Massachusetts.

[15] On March 25, 1953, Spinney was involved in a massive 15 player trade with the new, second version of the Baltimore Colts — a straight 10-for-5 swap of contracts in which no additional money changed hands.

[16] Joining Spinney in making the move from the mighty Browns to the expansion Colts were such future starters as defensive backs Don Shula, Bert Rechichar, and Carl Taseff, as well as veteran guard Ed Sharkey.

[19] He was offered a place on the staff with the Miami Dolphins by head coach Don Shula but declined the opportunity, preferring to stay in New England and to start a family.

In 1972, along with Lawrence J. Warnalis of Medford, Massachusetts, Spinney was awarded a patent for Biltrite's artificial turf product, Poly-Turf, a composite surface for football or soccer fields using additional layers of shock dissipating and shock-absorbing material.

King, a former college teammate, said of Spinney, "He was the toughest single person I ever encountered, he handed out punishment with clean hard-hitting, but he'd play himself into total fatigue.