State Sen. Fred Jarrett of Mercer Island will join the administration of the new county executive, Dow Constantine, as deputy executive, the highest ranking staff position in the incoming administration, Constantine announced Tuesday.

Jarrett ran against Constantine in the primary election. His 41st Legislative District includes part of the northern Renton.

Jarrett will resign from his Senate seat to oversee the day-to-day operations of King County. The 41st District is also represented by House Reps. Marcie Maxwell and Judy Clibborn.

Jarrett has a long career in public and private service. He is a former Mercer Island mayor, a retired Boeing executive and an experienced legislator, having served in the House.

“Fred’s willingness to assume this leadership role will assure that the ideas he and I shared on the campaign trail, and those generated by our large, diverse transition team, will be carried forward at the County,” Constantine said in a press release “I cannot think of a more perfect fit to address the challenges and opportunities that we face while we remain true to our core values.”

Constantine indicated he’s adding some responsibilities to the deputy executive’s position, essentially making the job the county’s chief operating officer.

In the press release, Jarrett indicated he was honored to accept this key leadership role in the Constantine administration and was eager to move forward on implementing Constantine’s reform agenda once the new administration takes over on Nov. 24.