He attended Alhambra High School, where he earned All-Southern California prep football honors.
He was also courted by the San Diego Chargers of the rival American Football League (AFL).
[4] He was originally slated to play defensive back at the time of his entry into the league, but due to his size and speed he impressed as an offensive receiver at the Rams' 1961 training camp and was switched to that position.
[2] Allen's sophomore campaign with the Rams in 1962 would be a brief one, catching a touchdown against the San Francisco 49ers on October 28 before being forced to leave the game with a season-ending knee injury.
[5] Allen ultimately spent seven years in the NFL playing for the Los Angeles Rams (1961–64), Pittsburgh Steelers (1965), and Chicago Bears (1966–67).