Willson Contreras was promoted to the Cubs major league team on June 17, 2016, playing catcher. On June 19, he hit a two-run home run on the first pitch of his first major-league at-bat becoming the 30th player in the modern MLB era to do so. In his fifth game, he started at first base, and started in left field in his eighth game, establishing himself as a versatile player on the field.

Contreras finished the 2016 regular season with 80 hits in 295 at bats with 12 home runs, 56 RBI's and a .275 batting average. In Game 4 of the 2016 National League Division Series against the San Francisco Giants with the Cubs having a 2-1 series lead, Contreras had a pinch-hit two-run single in the top of the ninth inning, tying the score at 5. The Cubs scored the go-ahead run later that inning, sending them to the NLCS. The Cubs went on to win the 2016 World Series over the Cleveland Indians, giving the Cubs their first championship in 108 years.

On April 2, 2017 Contreras was the Cubs opening day starting catcher against the St. Louis Cardinals.

This 27" x 37" Chicago Cubs "W" flag was signed in black by Contreras and includes a Schwartz Sports hologram and COA.