Maroon was drafted by the Philadelphia Flyers in the sixth round, 161st overall, in the 2007 NHL Entry Draft. He was assigned to the Flyers American Hockey League (AHL) affiliate team, the Phantoms in 2007.
During the summer of 2010, Maroon led the United States men's national inline hockey team to a gold medal performance at the 2010 IIHF InLine Hockey World Championship. He scored seven goals and 14 points in six games at the in-line worlds including a goal and an assist in the gold medal game in Karlstad, Sweden, against the Czech Republic.
After nine games of the 2010 –11 season, Maroon led the Adirondack Phantoms in scoring with 5 goals. He was expected to make the jump to the NHL with the Flyers that year, but on October 30, 2010, he was suddenly dismissed from the Phantoms for an undisclosed incident.
Three weeks later, on November 21, 2010, Philadelphia traded Maroon and David Laliberte to the Anaheim Ducks in return for forward Rob Bordson and defenseman Danny Syvret.
Shortly after the trade, Maroon was assigned to Anaheim’s AHL affiliate, the Syracuse Crunch, in Syracuse, New York. He scored 11 minutes 10 seconds into his first game with the Crunch, with whom he scored 21 goals and 48 points in 57 games.
The 2013–14 campaign was Maroon's first full season in the NHL. He appeared in 62 games, scoring 11 goals to go with 18 assists and despite having a year to run on his contract was signed to a three-year contract extension on August 2, 2014. He would appear in 71 games in his next season, scoring nine goals with 25 assists. His offensive game came alive in the 2015 Stanley Cup Playoffs, scoring eight goals in 16 games while playing on the Ducks' top line. Maroon's ability to create time and space for his line mates Ryan Getzlaf and Corey Perry by his hard work and fierce battles in the corners, led to his playoff production increasing as he found himself open in key moments of the series and he capitalized by lighting the lamp.
In the 2015 –16 season, Maroon found himself playing with the fourth line for the Ducks at the beginning of the season. At times his play was exemplary and other times he often saw his ice time drop to below 10 minutes a game. He was reunited with Corey Perry and he found his scoring touch, picking up consecutive points in consecutive games, while scoring just 4 goals and 13 points in 56 games before on February 29, 2016, he was traded to the Edmonton Oilers in exchange for a 2016 fourth-round draft pick and prospect Martin Gernát. In his first four games as an Oiler, Maroon scored two goals and added two assists.
In the first game of the 2016-17 season on October 12 Maroon scored the first goal in the Oilers brand new arena, Rogers Place, in a 7-4 victory over the Calgary Flames. On January 5th 2017, Maroon scored his first career hat-trick against the Boston Bruins in an Oilers 4-3 win.