Arnett filed a divorce petition in Los Angeles Superior Court on April 8 citing irreconcilable differences. His filing seeks joint custody of the pair's two sons, who are ages 3 and 5.
The actors announced they were separating in September 2012 after nine years of marriage.
They were married in 2003 and have maintained successful careers, with Poehler starring in NBC's "Parks and Recreation" and Arnett starring in CBS' series "The Millers."
The court filing was first reported Wednesday by People magazine.