Kellett is credited as the general manager who brought Pittsburgh Steelers cast-off Johnny Unitas from semi-professional sandlots to superstardom in the NFL.

A three sport star at the University of Pennsylvania from 1932 to 1934, Kellett also had a brief playing career in Major League Baseball as an infielder for the Boston Red Sox.

[1] This drew the attention of the Boston Red Sox, who signed him to a professional baseball contract which included a $5,000 bonus, a substantial sum for the era.

In autumn 1935, he was named head coach for the freshmen football and basketball teams at Ursinus College in Collegeville, Pennsylvania.

[2] After being granted a new franchise in the National Football League for the 1953 season, the Baltimore Colts named Kellett their first team president and general manager.

He was supported by four team owners who opposed the candidacy of Marshall Leahy due to his plan to move the league office to San Francisco.

[4] After eight days of deadlock, Los Angeles Rams general manager Pete Rozelle was selected as a compromise candidate.

[6] Although he had suffered one heart attack while still working for the Colts, his health was presumed excellent, commenting to reporters shortly before his death that he had his weight "back to where it was when I played football in college.