Gerbe was selected by the Buffalo Sabres in the fifth round (No. 142) of the 2005 NHL Draft after two seasons with USA Hockey's National Team Development Program. He won a national championship with Boston College in 2008, the same year he was named a finalist for the Hobey Baker Award, given to the top college player, after he scored 35 goals and 68 points in 43 games. He was selected the Frozen Four Most Outstanding Player after scoring five goals in two games.

Gerbe left college after his junior season and signed an entry-level contract with the Sabres. He made his NHL debut against the Tampa Bay Lightning on Dec. 6, 2008 but played the majority of the season with Portland of the American Hockey League, where he was named the AHL's top rookie with 30 goals and 56 points in 57 games.

He set a Sabres record on Jan. 21, 2011 by scoring two goals in five seconds against the New York Islanders, one second short of the NHL record.

Gerbe's contract was bought out by the Sabres following the 2012-13 season, and he signed with the Carolina Hurricanes on July 26, 2013. He scored 16 goals and 31 points in 2013-14 and signed for two more seasons on June 24, 2014.

Gerbe signed a one-year contract with the New York Rangers on July 1, 2016 but never played a regular-season game for them. After failing to make the team out of training camp, he opted to play in Switzerland. Gerbe returned to North America on Jan. 24, 2018, when he signed with the Blue Jackets.

Gerbe scored 32 points (10 goals, 22 assists) in 41 games for the Blue Jackets' AHL affiliate in Cleveland in 2018-19. His 30 games played with Columbus in 2019-20 are the most he's played in the NHL since 2015-16.