- Mr Paxton, an ally of former President Donald Trump, is now suspended from office pending a trial in the Senate.
- A two-thirds vote in the upper chamber - where Republicans also dominate - is required to permanently expel him.
Texas' Republican-run House of Representatives has voted to impeach state Attorney General Ken Paxton, a Republican, who is accused of bribery and abuse of public trust.
Mr Paxton, an ally of former President Donald Trump, is now suspended from office pending a trial in the Senate.
A two-thirds vote in the upper chamber - where Republicans also dominate - is required to permanently expel him.
Mr Paxton, aged 60, denies all the accusations against him.
Responding to a 121-23 vote in the House on Saturday, Mr Paxton said in a statement: "The ugly spectacle in the Texas House today confirmed the outrageous impeachment plot against me was never meant to be fair or just.
"It was a politically motivated sham from the beginning."
The impeachment vote was on 20 articles, which also include accusations of improperly aiding a wealthy political donor and conducting a sham investigations against whistleblowers.
The result demonstrates a very public split between Texas Republicans.
"Attorney General Paxton continuously and blatantly violated laws, rules, policies and procedures," House Republican David Spiller said.
"Today is a very grim and difficult day for this House and for the state of Texas," he added.
But John Smithee, another Texas House Republican, opposed the impeachment, arguing that the attorney general had not been given the chance to properly respond to the allegations against him.
"It's what I call the hang him now and judge him later policy," Mr Smithee said.
Meanwhile, Mr Trump - who hopes to win a Republican nomination for the 2024 election - backed Mr Paxton.
Shortly before the vote, he wrote "free Ken Paxton" in a post on social media.
The House vote makes Mr Paxton the first state official in Texas to be impeached in almost 50 years.
Texas' Republican Governor Greg Abbott has the powers to appoint an interim state attorney general even before the Senate trial is concluded.
Mr Paxton is well-known in America for his high-profile litigation campaigns.
In 2020, he unsuccessfully pressed the US Supreme Court to overturn Mr Trump's defeat to Democratic challenger Joe Biden in the presidential election.
Five years earlier, Mr Paxton called the Supreme Court's decision legalising gay marriage in all 50 states a "lawless ruling", vowing to support state workers who refuse to marry couples on religious grounds.
But he is perhaps best known for spearheading the ongoing fight in the courts to challenge the Biden administration's changes to the immigration system.
Mr Paxton has said the measures he is fighting would encourage illegal crossings and burden Texas and other states with additional expenses for law enforcement, health care and education, the New York Times reports.