Morris's wife, Kay, said the cause was complications of dementia. A geriatric psychiatrist who had treated Morris said he believed his condition was related to football contact. Mrs. Morris said that her husband first displayed symptoms in his mid-50s and that he had spent the last four years at a nursing facility, where he died.

Known as the Brahma Bull for his bruising play as an all-American at Georgia Tech and as an 11-year professional, Morris was named to the N.F.L.'s all-decade team for the 1960s.

His signature moments came on Dec. 29, 1963, when the Bears played the Giants for the league championship. The temperature was about 10 degrees at kickoff, but nearly 46,000 fans jammed Wrigley Field.

The Bears had allowed a little more than 10 points a game in the regular season, but Tittle had thrown a league-leading 36 touchdown passes.

Morris was playing at outside linebacker in a defense that also featured his fellow All-Pros Bill George and Joe Fortunato at linebacker, Doug Atkins at end and Richie Petitbon and Roosevelt Taylor in the secondary.

The Giants were leading, 7-0, in the first quarter when Morris intercepted a screen pass by Tittle and ran it back 61 yards to the Giants' 6, leading to a touchdown.

"I was so tired I knew I was going to get caught," the 6-foot-2-inch, 226-pound Morris said after the game.

His former teammate Johnny Morris, a leading receiver for the Bears, recalled in an interview Sunday how he "had pretty good speed for a linebacker" and "was as effective against the pass as the run."

Larry Morris had plenty of energy left after his long run with the interception. In the second quarter, with the Giants leading by 10-7, he downed Tittle as he delivered a pass. Morris's helmet struck Tittle's left knee, and he landed on it awkwardly, sidelining the quarterback for the rest of the half with damaged ligaments.

Tittle later returned but had difficulty setting up for passes and threw five interceptions in the Bears' 14-10 victory.

Larry Cleo Morris was born on Dec. 10, 1933, in Atlanta. He played on two unbeaten teams at Georgia Tech under the longtime coach Bobby Dodd.

Morris was a first-round draft pick of the Los Angeles Rams in 1955. He played three seasons for the Rams, seven for the Bears and a final season for the Atlanta Falcons. He was elected to the College Football Hall of Fame in 1992.

Morris was a real estate developer in the Atlanta area after retiring from football. But his wife said that much of the family's financial resources were depleted by his poor business decisions that appear to have been related to the early stages of his dementia. Morris's family provided his brain to a center at Boston University that conducts research on the brains of former football players and others who sustained head trauma to determine its links to long-term degenerative brain disease.

Appearing in September 2007 before a United States Senate committee studying disability issues facing retired players, Daryl Johnston, the former Dallas Cowboys fullback and football broadcaster, said that Morris had played through four concussions.

The Morris family has received assistance from an N.F.L. players' union fund that provides up to $88,000 a year for the care of retired players with dementia.

In addition to his wife, Morris is survived by his sons Britt, Chris and Shan; his daughter, Kayanne Staub; and 12 grandchildren.

In reflecting on Larry Morris's career, Johnny Morris said that Larry Morris had "an easygoing personality" although he was "a great player in a violent game."