Roach was the backup quarterback on the Packers' 1961 and 1962 NFL championship teams, backing up Bart Starr under head coach Vince Lombardi. In 1963, when Starr injured his passing hand in the sixth game against the St. Louis Cardinals, he was held out for 4½ games and Roach was named the starter during those contests. The team was 4–1 with Starr sidelined and finished 11–2–1, but the 26–7 loss to the Chicago Bears in mid-November was critical; keeping them a half game back in the Western Conference final standings and denied the Packers a chance to win an unprecedented third consecutive NFL championship game.