John Whitmire resigns from Texas Senate as he prepares to become Houston's next mayor

HOUSTON, Texas (KTRK) -- Before he takes over at Houston's City Hall in January, John Whitmire announced Friday that he has officially resigned from his position as state senator.

Whitmire, Texas' longest-serving state senator, defeated Congresswoman Sheila Jackson Lee in a mayoral runoff election on Dec. 9.

The video above is from ABC13's conversation with Mayor-elect Whitmire, who sat down with Tom Abrahams to share his administration's priorities on our weekly political show, "This Week in Texas."

That means he'll now lead the country's fourth-largest city as it 63rd mayor, but he also must give up his old post.

Whitmire, 74, is replacing term-limited Mayor Sylvester Turner, who was first elected in 2015 and took office in January 2016.

In his letter to Texas Gov. Greg Abbott shared Friday morning, Whitmire noted his political career, which started with him serving as a state representative from 1973 to 1983.

He became a state senator in 1983 and has served in that role since.

"I have served during the tenure of 7 Governors, 6 Lieutenant Governors, 8 Speakers and hundreds of outstanding legislators," Whitmire wrote. "I believe public service is a calling and I have worked alongside some of the finest public servants this state and country have ever known."

You can read Whitmire's full letter to Abbott by following this link.

Whitmire's resignation from the office of Texas State Senator, District 15, will go into effect at 10 p.m. on Dec. 31.

He'll be inaugurated just two days later on Jan. 2, 2024.

READ MORE: Houston mayor-elect John Whitmire intends to make City Hall 'user-friendly'