In return, Edmonton sent prospect Martin Gernat, a defenceman, and a 2016 fourth-round pick to the Ducks.
“We got a little bigger,” Oilers general manager Peter Chiarelli said.
Maroon is listed at six foot three and 230 pounds. He’s been a third- and fourth-line player with Anaheim this year, averaging just over 11 minutes per game.
Maroon has four goals and nine points along with 54 penalty minutes in 56 games.
The 27-year-old had played his whole career with Anaheim and comes with a cap hit of $2 million US annually in each of the next two years. The Ducks will retain $500,000 of Maroon's cap hit for both remaining years.
Also on Monday, Chiarelli picked up two players off the waiver wire: Adam Cracknell from Vancouver and Adam Pardy from Winnipeg.
Both will join the team in Buffalo, N.Y., where the Oilers play the Sabres on Tuesday night.
Cracknell, 30, is a six-foot-two, 210 pound right winger. He has five goals and five assists in 44 games with the Canucks this year.
Pardy, 31, has one assist in 14 games with the Jets.
Chiarelli said Cracknell is needed as forward Benoit Pouliot was injured in Sunday's 3-1 win over the New York Islanders.
``I don't know the prognosis yet ... (but) it could be four or five weeks or it could be the rest of the year (on Pouliot),'' said Chiarelli.
Chiarelli is in his first season as Edmonton's GM and has said he wants a bigger, heavier team.
Over the weekend, he traded backup goalie Anders Nilsson, defenceman Justin Shultz and forward Ted Purcell for a minor-league goaltender and draft picks.
Edmonton also signed defenceman Brandon Davidson and goaltender Laurent Brossoit to two-year contract extensions Monday.
Davidson, 24, a 2010 sixth-round pick, has emerged as one of Edmonton's steadiest defencemen. The six-foot-two, 210-pound Davidson had a goal and an assist Sunday against New York, his first multi-point game, while leading the team with over 22 minutes of ice time.
Davidson's career was almost derailed before it began when he was diagnosed with testicular cancer in 2012. There was surgery and chemotherapy, loss of weight, loss of strength, followed by a three-year apprenticeship in the minors.
The native of Lethbridge, Alta., said it was difficult but necessary.
``I was a little bit of a late developer for sure,'' he said. ``I needed the time, I needed the amount of minutes and the heavy workload (in the minors).''
Oilers head coach Todd McLellan said Davidson's play has been head-turning.
``Right now perhaps he's our Cinderella story, which in turn will put a little more pressure on him this time next year,'' McLellan said. ``Expectations will go up.''
Brossoit, 22, of Surrey, B.C., has been solid this season with the AHL's Bakersfield Condors. He has compiled a 15-9-3 record, 2.69 goals-against average and .919 save percentage with three shutouts.
He has played in two career games with the Oilers, registering a 1.45 GAA and .964 save percentage.
Chiarelli has said Brossoit's play made it possible for the team to send Nilsson to the St. Louis Blues on Saturday for minor-league goalie Niklas Lundstrom and a 2016 fifth-round pick.
``I'm nothing but excited,'' said Brossoit. ``They've reiterated the fact that they have a lot of faith in me.
``That goes a long way for my confidence.''