Adam was acquired by the Reds from the San Francisco Giants, along with RHP Keury Mella, in exchange for RHP Mike Leake on July 31, 2015. In his major-league debut with the Giants at AT&T Park on June 26, 2014, Duvall had recorded his first big-league hit – a home run – off Leake.
In his first full major-league season in 2016, Adam was selected to his first All-Star team by the players, managers and coaches. He ranked among the National League leaders with 33 home runs (T-6th) and 103 RBI (5th) last season. Adam homered an average of once every 16.7 at-bats in 2016, sixth-best in the NL, and led the Reds in triples (6), home runs (33), RBI (103) and extra-base hits (70). He became the ninth player in Reds history with at least 31 doubles, 33 HR and 103 RBI, the first since Joey Votto went 36-37-113 in his 2010 MVP season. Adam is also the 13th player in Reds history with at least 30 doubles, 30 HR and 100 RBI in a season.
Despite playing in only 28 games for the San Francisco Giants in 2014, Adam was rewarded by the club with a World Championship ring.