In the penultimate regular season game with the Cleveland Browns on December 8, hall of fame quarterback Bobby Layne was lost for the season with a broken right ankle. With backup Tobin Rote in at quarterback in the second quarter, the Lions won that game and overcame a ten-point deficit at halftime the following week to defeat the Chicago Bears 21–13, whom they had lost to three weeks earlier at home. They ended the regular season with three consecutive wins and an 8–4 record. All four losses were within the Western Conference, splitting the two games with all but the Green Bay Packers, whom they swept.
Detroit tied with the San Francisco 49ers (8–4) for the conference title, which required a tiebreaker playoff game. Played at Kezar Stadium in San Francisco on December 22, the 49ers entered the game as three point favorites. Down by twenty points in the third quarter, Detroit rallied with a 24–0 run to win 31–27.
On September 29, 1957, the Lions opened their 1956 with a 34-14 loss to the Baltimore Colts in Baltimore. The Colts were led by Johnny Unitas who threw four touchdown passes and the Baltimore defense that held the Lions to 23 rushing yards and intercepted three of Bobby Layne's passes. Detroit's touchdowns were scored by Howard Cassady (a short run for his first NFL touchdown) and Jerry Reichow on a 32-yard pass from backup quarterback Tobin Rote.
On December 22, 1957, the Lions defeated the San Francisco 49ers, 31-27, in a Western Conference playoff game. The 49ers took a 24-7 lead at halftime, as Y. A. Tittle threw three touchdown passes in the first half. After falling behind 27-7 early in the third quarter, the Lions responded with 24 unanswered points. Detroit's touchdowns were scored by Steve Junker on a four-yard pass from Tobin Rote, two runs by Tom Tracy (1-yard and 58-yard runs), and Gene Gedman on a two-yard run.
On December 29, 1957, the Lions defeated the Cleveland Browns, 59-14, in the 1957 NFL Championship Game. The Browns had been favored to win by three points. Tobin Rote, filling in at quarterback after Bobby Layne broke his ankle, was credited with "a brilliant performance" as he completed 12 of 19 passes for 280 yards and four touchdowns and rushed for a touchdown, leading the Lions to "their greatest point total in history on offense." The Lions capitalized on five interceptions and two fumble recoveries, including a 19-yard interception return for touchdown by Terry Barr, and held Cleveland star Jim Brown to 69 rushing yards on 20 carries. The longest pay of the game was a 78-yard touchdown pass from Rote to Jim Doran. Rookie Steve Junker was the Lions' leading scorer with 12 points on touchdown receptions covering 26 and 23 yards. Jim Martin followed with 11 points on eight extra point conversions and a 31-yard field goal. The victory gave the Lions their third NFL championship in six years. It was also referred to as "the perfect revenge" for the Browns' 56-10 defeat of the Lions in the 1954 NFL Championship Game.