Bell joined the Boston Patriots in February 1971, and at age 33, was the NFL's youngest general manager. Without a permanent location, games were played at multiple locations around Boston including Fenway Park, Harvard, and Boston College. One of Bell's first moves was recommending to the Patriots' board of directors that they change the name from the proposed Bay State Patriots to New England Patriots, as the team relocated from Boston to Foxborough, Massachusetts.

Bell later hired Bucko Kilroy and put together the Patriots' first scouting department. To further fill out the scouting department, Bell hired Tom Boisture, Dick Steinberg, Mike Hickey, and Bob Terpening, all of whom went on to head scouting positions in the NFL. Bell hired as assistant general manager Peter Hadhazy, who later became general manager of the Cleveland Browns. Bell also brought the team to UMass Amherst for training camp at the school’s McGuirk Stadium.

Under Bell's leadership, the Patriots improved from their 1970 record of 2–12 to 6–8 in 1971. Despite the improvement, Bell wanted to fire head coach John Mazur and hire a coach of his own choosing. The team's board of directors agreed that if the Patriots lost to the Baltimore Colts in the final week of the regular season, Mazur would be fired. The Patriots won, 21–17, helped by an 88-yard touchdown pass from Jim Plunkett to Randy Vataha in the fourth quarter. The Patriots fell to 3–11 the following season, and Bell was fired on December 5, 1972.