Baltimore Colts

Dupre was selected by the Baltimore Colts in the third-round (27th overall) of the 1955 NFL Draft. As a rookie, he was second on the team in rushing (behind Alan Ameche), registering 88 carries for 338 yards, with most of his production coming after the fifth game.

In 1956 with the addition of rookie Lenny Moore, he was forced to develop into a receiver out of the backfield and was third on the team with 216 receiving yards. His production would decrease in the following seasons, with Moore taking a bigger role in the offense. He also was a part-time punter.

In 1957, he was fourth on the team with 32 receptions for 339 yards. He was a part of the 1958 NFL Championship Game against the New York Giants, famously known as "The Greatest Game Ever Played". He started the game by gaining 30 yards on 10 carries.

In 1959, Dupre played in only the first 4 regular games of the season. His only touchdown was a 2-yard pass from John Unitas against the Chicago Bears on October 18. He sustained a season-ending injury while driving home from a Tuesday practice. He put on the brakes and felt something pop in his leg, that caused ruptured blood vessels in his thigh. Dupre was a member of the 1959 Baltimore Colts championship team, but due to his injury, he did not play in the rematch against the Giants, which the Colts won 31-16. Halfback Mike Sommer substituted for Dupre in the 1959 NFL Championship Game.

Hall of Famer Art Donovan had this to say of Dupre: "But the running back who was really something, the guy who could really fight, was a teammate of mine named L.G. DuPre. Louis George DuPre to his family; Long Gone DuPre to the rest of the world. Long Gone grew up in Texas City, Texas, the oil refinery town that blew up back in the 1940s. He was playing hooky from school that day and was out fishing at the end of a jetty, so he wasn't hurt. But L.G. had an amazing childhood, primarily because his father used to bring L.G. and his brother into barrooms and let them fight each other while he passed the hat. They used to whale the tar out of each other, from what I understand. I met his father once. And I asked him if the story was true. Mr. DuPre said, 'Sure is, son. We used to pass the hat. Turned quite a nice dollar, too.' Now, that is one tough sonofabitch. And L.G. grew up just like his daddy. He wouldn't take a back step to anyone. All these other galoots in the league, they'd just swing and get swung at during a rumble. Their heads were all hard enough to withstand just about anything. But L.G., there was a scientific fighter. I can still picture him out in the middle of some brawl on the field feinting and jabbing and, boom, he'd unload that right hand and coldcock the poor sucker who was foolish enough to be mixing it up with him."^[3]

Dallas Cowboys

Dupre was selected by the Dallas Cowboys in the 1960 NFL Expansion Draft. In the Cowboys 1960 inaugural season, he led the team in rushing with 104 carries for 362 yards in 11 games (5 starts). He also scored 3 touchdowns in the tie against the New York Giants, helping avoid losing all of the games in the season.

In 1961, his role was reduced with the emergence of Don Perkins and Amos Marsh. He was released on September 4, 1962.^[4]

A Baltimore Sun article on October 2, 1962, indicated that the Baltimore Colts were interested in signing him to replace Lenny Moore, in case his injuries were serious enough to keep him from playing. The Sun reporter spoke with Dupre's wife in Dallas and she explained that Dupre had to first check with his employer (General Electric) about a leave of absence. She indicated that he had a good job and did not want to lose it. His wife was still Sissy Dupre. He stayed retired from professional football and did not return to Baltimore.