[1] Hewitt played college football for the Michigan Wolverines, where he was named team's most valuable player and second-team All-Big Ten his senior season.

He started in two games each in 1929 and 1930,[2][3] and in 1931 was a first-team All-Big Ten selection from the United Press,[4] as well as the Wolverines' team MVP.

[6] Against Minnesota, he scored the only touchdown of the game on a 57-yard run to help Michigan secure that year's Little Brown Jug trophy with a 6–0 win.

[9][10] He played without one until 1939, his final season with the Eagles, due to new league rules requiring players to wear a helmet.

[16] Hewitt led the league in receiving touchdowns in 1934, with five,[17] and was named a first-team All-NFL selection for the third time in as many years.

[19] After considering retirement, Hewitt was traded to the Philadelphia Eagles with $4,000 in cash from the Bears in exchange for the rights to the first overall selection in the 1937 NFL draft, Sam Francis, on February 15, 1937.

[19] In November 1939, Eagles president Bert Bell announced Hewitt would be retiring at the end of the season after eight years in the NFL.

[21] In his final home game with the Eagles, against the Pittsburgh Pirates, he was the middle man of a 66-yard play as he received a 26-yard pass from Davey O'Brien and lateraled to Jay Arnold, who ran 40 yards for the touchdown.

[23] After being out of football for three seasons, Hewitt returned in 1943 to play fullback for the Steagles, a temporary merger of the Eagles and Pittsburgh Steelers during World War II.

Hewitt's jersey number 56 is retired by the Bears,[31] and he is enshrined in the Philadelphia Eagles Hall of Fame.