A former speaker of the Ohio State House of Representatives, now serving a 20-year federal prison sentence, was indicted on 10 more state felony charges on Monday in connection with a sprawling bribery scheme that handed a $1.3 billion bailout to a major regional energy utility.

The charges against the former speaker, Larry Householder, followed an inquiry by the Ohio Organized Crime Commission that also produced indictments last month of two former executives of the Akron-based utility, FirstEnergy Corporation.

The two men — Chuck Jones, a former FirstEnergy chief executive officer, and Michael Dowling, a senior vice president — were charged with funneling $4.3 million in bribes to the former chairman of the Ohio Public Utility Commission, Sam Randazzo. They and Mr. Randazzo, who was also indicted, have pleaded not guilty to a total of 27 charges.

The FirstEnergy case has been called the largest political scandal in Ohio history. Mr. Householder was convicted of accepting $60 million in bribes in exchange for shepherding into law a mammoth bailout of two unprofitable nuclear power plants owned by a subsidiary of the utility, as well as two coal-fired electric plants and solar energy projects.

Mr. Householder, 64, is appealing his racketeering conviction, which took place in federal court last June. Among other things, the new state charges assert that he illegally tapped a campaign account to pay $750,000 in legal fees for his defense and that he failed to disclose loans, debts, legal fees and gifts from lobbyists in ethics statements required of members of the state legislature.

The charges — three counts of theft, five counts of record-tampering and single counts of money laundering and telecommunications fraud — could permanently bar Mr. Householder from public office if convicted.

He had been investigated on suspicion of public corruption earlier in his legislative career, after a first stint as House speaker in the early 2000s, but that inquiry ended without charges.

“State crimes have state penalties, and a conviction will ensure that there will be no more comebacks from the ‘Comeback Kid,’” the Ohio attorney general, Dave Yost, said.

At a news conference, Mr. Yost declined to say whether more charges were forthcoming.

Some of the money personally benefited Mr. Householder, a Republican, but more dollars went elsewhere — $17 million for a media campaign backing the bailout, known as House Bill 6, and more for private detectives, people paid to intimidate those gathering signatures for a ballot initiative to overturn the bailout, and advertising to thwart that campaign, which was led by clean-energy advocates and the natural gas industry.

Millions more were secretly funneled into political action committees that donated to the campaigns of 21 Republican state legislative candidates who backed Mr. Householder’s return to the speaker’s chair.

When federal agents arrested him in July 2020, Mr. Householder was angling to change the State Constitution’s term limit clause so he could serve an additional 16 years in office. A lobbyist and an aide to Mr. Householder faced federal charges but cooperated in the investigation. A second lobbyist, Neil Clark, pleaded not guilty before taking his own life in 2021.

FirstEnergy, a Fortune 500 company, admitted a role in the scheme in 2021. A second regional utility based in Columbus, American Electric Power, is being investigated by the Securities and Exchange Commission in connection with House Bill 6, which also weakened Ohio’s renewable energy standards.