He began his career in 1958 with the CFL with the Toronto Argonauts before joining the NFL's San Francisco 49ers the next season.

Prior to the event, the University of Texas did not want him to attend the game, but the USC players refused to play without him.

After being drafted in the 14th round of the 1958 NFL draft by the New York Giants, Roberts opted instead to sign with the Toronto Argonauts of the "Big Four" (soon to be renamed the Eastern Conference) of the Canadian Football League, whose head coach was fellow Californian Hamp Pool.

[1] After 10 games in double blue, however, he became a casualty of the 12-man import quota limiting the number of US players who could suit up for the Argos, and was released by Pool in favor of the more versatile Jim Rountree, a defensive standout.

Even during his NFL career, Roberts, who held a Masters of Business Administration degree, worked in the off-season as an independent building contractor.