House Speaker Mike Johnson's (R-LA) thin GOP majority is a little smaller after Rep. Mark Green (R-TN) resigned his seat.

The Tennessee Republican officially stepped aside Sunday, weeks after announcing his early retirement from representing the 7th district.

Green had promised to stay on the job until Trump's mega bill cleared Congress, which it did earlier this month.

“It’s with a heavy heart that I say farewell. To my constituents across Tennessee’s 7th District—thank you. The trust you put in me is humbling. I will look back fondly on my years of serving as your voice in Washington," he wrote on X.

GOP lawmaker resigns

Green's district is solidly Republican, so his resignation is unlikely to tip the balance of power in Washington. But Johnson has less room for error until another Republican replaces Green.

The party's razor-thin majority made passing Trump's Big, Beautiful Bill a challenge, with multiple factions competing to press their demands. Trump's One Big Beautiful Bill Act received final House approval on July 3, with two Republicans voting no.

"Though I planned to retire at the end of the previous Congress, I stayed to ensure that President Trump’s border security measures and priorities make it through Congress," Green said.

A former flight surgeon who served tours in Iraq and Afghanistan, Green was elected to Congress in the 2018 midterms.

As chairman of the Homeland Security Committee, Green led the GOP's impeachment of former Homeland Security Secretary Alejandro Mayorkas.

Plagued by scandal

Green's tenure was rocked by scandal when he was caught having an affair, which led Green to file for divorce from his wife.

Green's wife accused him of cheating on her with a journalist, although Green's wife later apologized for accusing the wrong woman. A different woman anonymously came forward and said she was in a relationship with Green.

Green has said he will take on a new job in the private sector, although he did not get into specifics. His resignation opens up a contentious special election in his solidly Republican district, with GOP candidates lining up for the job.

The House GOP Steering Committee selected New York Republican Andrew Garbarino, a moderate from Long Island, to replace Green as chairman of the Homeland Security committee.

“We have serious work ahead of us. Securing the border, confronting terrorism, strengthening our cybersecurity, and hardening our national defenses are all critical to keeping Americans safe," Garbarino said.