He is generally considered the first great passer in professional football. In 1926, Friedman earned the Chicago Tribune Silver Football Award as the Big Ten MVP. In 2005, Friedman was inducted into the Pro Football Hall of Fame.
Friedman became the starting quarterback and placekicker midway through his sophomore year at Michigan (On defense, he played in the backfield). In 1925 and 1926, he led the Wolverines to consecutive 7–1 seasons and first place finishes in the Big Ten Conference. Against Indiana in 1925, Friedman accounted for 44 points, throwing for five touchdowns and kicking two field goals and eight extra points. The following year, he was a consensus first-team All-American and most valuable player of the Big Ten.
In 1927, Friedman joined his hometown Cleveland Bulldogs in the National Football League. After a successful rookie season in Cleveland, he had a spectacular second year playing for the Detroit Wolverines. In 1928, Friedman led the NFL in passing touchdowns, rushing touchdowns and scoring as well as extra points (He may have led in other categories, too, but the NFL did not record yardage stats in those days.)
Friedman's performance so impressed New York Giants owner Tim Mara that Mara bought the whole Wolverines team just so he could have the rights to the quarterback. With the Giants in 1929, Friedman led the league again with 20 touchdown passes. Friedman's passing proficiency was especially noteworthy considering that most teams rarely threw the ball in those days. The football used at the time was rounder and more difficult to throw. Friedman called plays at the line of scrimmage and threw on first and second down, when most teams waited until third down. "Benny revolutionized football. He forced the defenses out of the dark ages." George Halas later said. No NFL team would surpass 20 passing touchdowns in a season until 1942. Friedman often experienced media bias because of his Jewishness, being referred to in the press by names like "Jew boy" and "descendant of Palestine"
In 1931, Friedman suffered a knee injury that hampered the rest of his career. He moved to the Brooklyn football Dodgers in 1932 as a player-coach while simultaneously serving as an assistant coach at Yale University. He led the league in completion percentage in 1933 and retired after the 1934 season. At the time of his retirement, he owned the NFL record for touchdown passes with 66.
After leaving the Dodgers, Friedman coached City College of New York until 1941. For decades afterward, the college's beaver mascot took on the moniker "Benny the Beaver." He served in the Navy during World War II. He then moved to Brandeis University in Massachusetts, where he served as athletic director from 1949 to 1961 and head football coach from 1951 to 1959, when the football team was disbanded as part of a cost-cutting effort.
Friedman suffered from heart disease and diabetes in his later years, requiring a leg amputation in 1978. Despondent over his health and inability to get into the Pro Football Hall of Fame, he took his own life in 1982.
Despite his impressive numbers, Friedman was not chosen for the Hall of Fame until 2005. Some people attributed this to his relentless self-promotion and campaigning for induction, which was considered bad form, while others attribute it to latent prejudice against him for his ethnic background.