Drafted in the third round of the 1951 NFL Draft out of Kansas, Mike McCormack began his professional career with the New York Yanks before stepping away to serve his country in the Korean War. By the time he returned from military service, the Yanks franchise had folded, and its assets were transferred to the newly formed Baltimore Colts. Legendary head coach Paul Brown had kept a close eye on the physical lineman and orchestrated a multi-player trade to acquire him before he ever suited up in Baltimore, bringing McCormack to Cleveland in 1954.

The transaction paid immediate dividends. McCormack stepped straight into the starting lineup at middle guard, famously securing a game-changing fumble recovery in the 1954 NFL Championship Game victory over Detroit. He transitioned to right tackle the following season, anchoring the offensive front for Otto Graham and clearing lanes for a powerful ground attack as Cleveland repeated as NFL Champions in 1955.

Over the next eight seasons, McCormack established himself as the premier offensive tackle of his era. Combining exceptional footwork with relentless leverage, he anchored the right side of the Browns' line through 1962, earning six Pro Bowl selections and four All-Pro honors during his tenure in Cleveland. Paul Brown famously called McCormack the finest offensive lineman he ever coached—high praise considering the hall-of-fame talent that passed through Brown's locker rooms.

McCormack retired after the 1962 season, following nine stellar years in Cleveland, having played in 108 regular-season games for the franchise and appearing in four NFL Championship Games.

His dominant career in the trenches was immortalized with induction into the Pro Football Hall of Fame in 1984, followed by his enshrinement in the inaugural class of the Cleveland Browns Ring of Honor in 2010.