In an email to constituents, Keam, 56, a Democratic attorney who has served in the House since 2010, said he was resigning for a job in the Biden administration that will require him to work full time.

“While I have loved every moment of the past thirteen years as your state legislator, I have decided to continue my public service in another capacity,” Keam said.

Keam’s departure won’t impact the balance of power in the House, where Republicans currently have a 52-48 majority. Last year, Keam was re-elected to his Fairfax County district, which includes the town of Vienna, with 68.7% of the vote.

At least one other Democrat, nonprofit leader Holly Siebold, Founder and Executive Director of BRAWS: Bringing Resources to Aid Women's Shelters, had already announced a run for the seat, and the field was already growing Tuesday with the news the incumbent was bowing out of the race.

Karl Frisch, a member of the Fairfax County School Board, announced his own candidacy for the seat a few hours after Keam broke the news.

It’s unclear when Democrats will pick a nominee or when a special election might take place.

In a statement, the Fairfax County Democratic Committee said it was working on “plans to operate an open and fair process to choose our nominee.”

“We thank Mark for more than a decade of public service in the House of Delegates and honor the history he made as the first Asian-born immigrant and the first Korean American elected to any state-level office in Virginia,” said Fairfax County Democrats Chair Bryan Graham.

The timing of Keam’s departure creates some legal uncertainty over the process to replace him.

All 100 House districts were redrawn last year, but several Democrats said a special election would be held under the old district boundaries to fill the remainder of Keam’s term, which was set to expire in 2024. That means whoever wins the seat will be running in a slightly different district next year if they choose to seek a full term.

Under state law, either the governor or the House speaker get to set the dates of special elections to fill vacancies in the General Assembly, depending on whether the legislature is in session or not. The General Assembly is still in a special session and will return to Richmond Wednesday to pick a new judge for the State Corporation Commission. But if House Speaker Todd Gilbert, R-Shenandoah, doesn’t formally set the election date by the time that session adjourns, the power to schedule the election will fall to Gov. Glenn Youngkin.

In his farewell message to constituents, Keam said he too did not know when a special election might take place to allow his district to pick a new representative for the 2023 legislative session.

“However, I am confident that our neighbors will be served well by anyone who is committed to the ideals of our nation which I cherish,” Keam said. “… Seeking to live free in a democracy is why my family and I came to America, and it is the core reason why I chose my public career path.”