Rep. Filemon Vela, D-Texas, resigned from Congress late Thursday, The Texas Tribune reported.
Vela last week confirmed he would resign to work for Akin Gump, a prominent lobbying and law firm.
"I write to inform you that I have notified Texas Governor Greg Abbott of my resignation from the U.S. House of Representatives, effective today at 11:59 PM EST," Vela wrote to House Speaker Nancy Pelosi, D-Calif., the Tribune reported.
"It has been a profound honor to represent the people of the 34th Congressional District of Texas for the last nine years, and my distinct pleasure to serve under your leadership."
Gov. Greg Abbott, R-Texas, now can set a special election date to determine who will serve for the remainder of Vela's unfinished term, which is a matter of months.
November's general election will determine who will represent Vela's 34th District and help decide which party will control Congress.
A recent National Republican Campaign Committee (NRCC) poll found that Republicans hold a four-point advantage over Democrats in battleground districts across the country ahead of the midterm elections.
Vela carried the 34th District by about 14 points in 2020.
Rep. Vicente Gonzalez, D-Texas, who represents the nearby 15th District, will switch to the 34th District in the general election due to redistricting. He has said he has no plans to resign from his current seat to run in a special election for Vela's unfinished term, the Tribune reported.
Any other Democrats interested in running for Vela's seat in the special election will be able to hold it only briefly — it's too late for new general election candidates.
Activist Mayra Flores, the Republican nominee for the November campaign, intends to run in the special election, the Tribune reported.
If Flores wins the special election, she would oppose Gonzalez in a rare U.S. House race between two incumbents.