Yonakor grew up in Boston, Massachusetts and played college football at the University of Notre Dame, where he was named an All-American on a team that won the national championship in 1943.

Yonakor spent four seasons playing primarily as a defensive end for the Browns as the team won four league championships between 1946 and 1949.

His son Rich was a star athlete in Euclid and went on to play one season for the National Basketball Association's San Antonio Spurs.

[3] Yonakor was set to go to Boston College, but chose the University of Notre Dame instead when Leahy became head football coach there in 1941.

[3] At Notre Dame in South Bend, Indiana, Yonakor played on the football team as an end beginning in 1942, when he was a sophomore.

[1][4][5] He was a starter at right end in 1943, when the Notre Dame Fighting Irish football team won the national championship under Leahy.

[5] Following the 1943 season, Yonakor spent two years in the U.S. Marines during World War II and played on military football teams.

[5] Creighton Miller, a teammate of Yonakor's at Notre Dame, took an assistant coaching position after the war with the Cleveland Browns, a team under formation in the new All-America Football Conference (AAFC).

[14] Yonakor went back home to Boston after ending his football career and worked in several sales jobs he found unsatisfying.

[11] His son, Rich Yonakor, was a star athlete in Euclid who played basketball in Italy and one season for the San Antonio Spurs in the early 1980s.