Davis wore number 87 during his career with the Packers. For 10 seasons, Davis anchored the Packers' defensive line, playing 138 consecutive regular-season games, part of 162 consecutive regular-season games for his NFL career. Davis was member to all 5 of Lombardi's NFL title-winning teams and played in Super Bowls I and II.
Davis played in an era when neither tackles nor sacks were official statistics. However, John Turney, a member of the Professional Football Researchers Association, and a painstaking, highly respected researcher/statistician, reports that his extensive research indicates Davis had in excess of 100 sacks during his 10-year Green Bay career (1960–69), "possibly more than 120," including a minimum of 40 over the 1963-65 seasons alone. Davis himself is quoted as saying, "I would think I would have to be the team's all-time leader in sacks. I played 10 years and I averaged in the 'teens' in sacks for those 10 years. I had 25 one season. (Paul) Hornung just reminded me of that the other day." Davis earned All-Pro honors 5 times (1962, 64-67). Meanwhile he was voted to the Pro Bowl five times (1963–67).
Davis recovered 21 fumbles over his Packers career, which, more than three decades removed from his retirement, remains a team record. The Packers honored his retirement with a Willie Davis Day on December 21, 1969. Davis remains on Green Bay Packers Board of Directors.