He later played professionally for the Chicago Bears of the National Football League (NFL) from 1948 to 1951, receiving first-team All-Pro honors in 1950.

Lujack was born to Alice and John Luczak,[3] in 1925 in Connellsville, Pennsylvania,[4] the youngest of four sons and fifth child in a family of six children.

[4] The family is of Polish descent and included older siblings Valentine ("Val"), Stanislaus ("Stan"), Victoria, Aloysius ("Allie", who went on to play professional basketball), and younger sister Dolores.

[3][9] Lujack's 1941 high school team, named the Cokers for workers in the coal milling industry who feed the ovens, went 8–0–1, but did not get to play for the WPIAL league championship because their last game, with Brownsville, ended in a 13–13 tie.

His career was interrupted for two years by World War II after his sophomore season, during which he served as an officer in the United States Navy.

[10] As he had in high school, Lujack once again received varsity letters (called "monograms") in four sports (again baseball, football, basketball, and track) while at Notre Dame, becoming the third person to do so.

He was the last Bears quarterback to throw at least five touchdown passes in a game until Mitchell Trubisky threw six against the Tampa Bay Buccaneers in 2018.

This record was tied by Tobin Rote with the Green Bay Packers in 1956, and broken by the New England Patriots' Steve Grogan in 1976.

[8][10] Leahy wanted Lujack to succeed him as the head coach of the Fighting Irish, but Terry Brennan was chosen instead by Reverend Theodore Hesburgh, the university president.

[8] The Johnny Lujack Training Facility was formally dedicated in 2009 and he was also inducted into the inaugural class of the Fayette County Sports Hall of Fame.

[12] His wife, the former Patricia Ann "Pat" Schierbrock (February 22, 1927 — August 2, 2022), was the daughter of Josephine (née Wilson) and Frank H.