He played youth football at the behest of a cousin, Dean Newby. After quitting, his cousin was angry. He called Gene a quitter, and tried to get him to come back. Shortly after, his cousin lost his life when mauled by a dog. When his aunt called him a quitter, too, he went back to football. After missing a couple of years to care for his terminally ill mother, he returned to school and found out that he excelled at football.[3]
He later dropped out of high school and joined the Navy where he played for a Navy team and was a star. After his discharge, he returned to Akron and worked at the Goodyear plant. Reading the paper in the lead up to the inaugural 1960 season, he read about a former opponent who had played for the Army who was signed by the Denver Broncos. He wrote them a letter and received a contract. He made the team without having played any college football.[4]
In 1960, he had the first punt return for a touchdown in the American Football League, for the Denver Broncos. That touchdown won the first-ever American Football League game, as the Broncos defeated the Boston Patriots. Mingo also scored the first points in Mile High Stadium, then called Bears Stadium, with an 18-yard field goal. In the 1961 season opener at War Memorial Stadium against the Buffalo Bills, Mingo threw a touchdown pass, from the halfback position, to help the Broncos win 22-10: a 50-yarder to Lionel Taylor in the first quarter. Mingo kicked the PATs after each score. He led the American Football League in scoring as a rookie in 1960 with 123 points and in 1962 with 137 points. Mingo holds the Broncos' franchise record for the longest touchdown run, an 82-yarder against the Raiders in 1962. He also played for the Oakland Raiders, Miami Dolphins, and Washington Redskins. He kicked for the Pittsburgh Steelers in 1969 and 1970.
