Alaska voters have elected a Democrat as governor for the first time since 1998, completing a midterm election wave that gave the party sweeping wins in state governments across the country.

The Associated Press called the race for former state lawmaker Jonathan Kreiss-Tomkins early on Saturday, after more than a week of counting ballots from the November 3 election. Kreiss-Tomkins, 37, defeated three Republicans, including Bernadette Wilson, a businesswoman endorsed by President Donald Trump.

Kreiss-Tomkins won 50.8 percent of first-choice votes, according to unofficial results, ahead of Wilson on 28.1 percent. Because he crossed 50 percent on the first count under Alaska's ranked-choice voting system, no further rounds of counting were needed. He will be the youngest governor in state history when he takes office at noon on December 7.

His victory means Democrats will control the governor's office in 30 states, up from 24 before the November 3 midterms, including states they flipped after years of Republican control such as Iowa, Georgia, Ohio and Texas.

Kreiss-Tomkins, often known as JKT, completed a political comeback three years after leaving the state House, where he represented Sitka. He finished first in August's open primary, ahead of a second Democrat, Tom Begich, who later withdrew from the race.

He defeated Wilson, former Anchorage mayor Dave Bronson and former state attorney general Treg Taylor. Alaska's Republican governor, Mike Dunleavy, who has served since 2018, was barred by term limits from seeking a third consecutive term.

Kreiss-Tomkins, who won his first state House race by 32 votes after a recount, has emphasised a willingness to work across party lines and said he wants a Cabinet with Republicans, Democrats and independents. His campaign did not immediately respond to requests for comment after the race was called.

The state's last Democratic governor, Tony Knowles, won re-election in 1998 and left office in 2002. Kreiss-Tomkins will serve alongside an independent lieutenant governor, Zac Johnson. The result remains unofficial until the state certifies the vote.