Foldberg played college football for Texas A&M University and the United States Military Academy, and thereafter, he played professionally for Brooklyn Dodgers and the Chicago Hornets of the All-America Football Conference (AAFC).

[2] He received an appointment to the United States Military Academy at West Point, New York, and played end for coach Earl Blaik's Army Cadets football team from 1944 to 1946.

Army produced back-to-back undefeated 9–0 records in 1944 and 1945,[3] and the Cadets were recognized as the Associated Press national champions following both seasons.

As a senior in 1946, Army was again undefeated at 9–0–1,[3] and Foldberg was recognized as a consensus first-team All-American at end.

[5] Foldberg resigned from the U.S. Military Academy in 1948, a year short of graduation, citing family financial hardship.

[2][16] He was unable to duplicate his successful turnaround of the Wichita Shockers program, compiled an overall record of 6–23–1 as the Aggies head coach,[11] and was replaced by Gene Stallings after the 1965 season.