Further information: 24th Alaska State Legislature Berkowitz was the Democratic Minority Leader in the Alaska House of Representatives from 1999 to 2007. He was first elected to represent District 26 in 1996, and reelected in 1998, 2000, 2002, and 2004.
In 2008 Berkowitz ran for election as U.S. Representative for Alaska's At-large congressional district, held by scandal-plagued RepublicanDon Young, who was seeking his 19th term in Congress. Berkowitz defeated Diane Benson in the August 26 Democratic primary by a substantial margin. The initial results from the general election on November 4, 2008, showed Young leading the race, but with many absentee and provisional ballots left to be counted, the race was not called. On November 12 the media declared that Young had been reelected. Berkowitz conceded defeat on November 18, after counting of absentee and provisional ballots had mostly been completed and Young had a clearly insurmountable lead. Ultimately Young received 50% of the vote to Berkowitz's 45%. Berkowitz received more votes in 2008 than any Democrat who had ever run against Young for Congress, and came the closest any Democrat had to unseating Young since 1990, when John Devens of Valdez received 48% of the vote.
2010 campaign
In December 2008 Berkowitz said he was considering challenging Young again in 2010, but in July 2009 he said he would not run and was instead considering challenging Governor Sarah Palin. Berkowitz entered the race following Palin's resignation in July 2009 and on August 24, 2010, he defeated State Senator Hollis S. French for the Democratic nomination. Incumbent Republican Governor Sean Parnell defeated Berkowitz and his running mate Diane E. Benson in the November general election, 59% to 38%.
2015 mayoral campaign
Berkowitz ran for mayor of Anchorage in 2015. He finished ahead of the rest of the field in the nonpartisan primary on April 7, advancing to a runoff with Assemblywoman Amy Demboski. Endorsed by the third-place finisher, former Republican state representative Andrew Halcro, he won the May 5 runoff election by a 19-point margin. Comments Berkowitz had made on the Bernadette and Berkowitz Show attracted controversy. In the context of a debate on October 13, 2014, with co-host Bernadette Wilson over same-sex marriage, Berkowitz had said, "I support the idea of adults being able to choose who they have a relationship with. Father and son should be allowed to marry, if they’re both consenting adults—if you’re defining marriage as the bundle of rights and privileges that’s now accrued to people, then yes." Berkowitz later called the remark a "hypothetical insinuation", denying that he supports incest.
Mayor of Anchorage
On July 1, 2015, Berkowitz was sworn in as Anchorage's mayor. In his inauguration speech he urged city residents and leaders to work to overcome differences and "rise above the immediacy and smallness of the moment".
Other ventures
Berkowitz took the position of Senior Vice President of the Anchorage, Alaska branch of Strategies 360 in February 2011. Berkowitz and Bernadette Wilson were co-hosts of the Bernadette and Berkowitz Show on Anchorage radio station KFQD in 2014. He left the show when he began his mayoral campaign.