Rep. Jonathan Steinberg, the Democratic co-chair of the General Assembly’s Energy and Technology Committee, said Thursday he will not seek a ninth term representing the 136th House District of Westport. 

Steinberg, 69, who said he has held the seat longer than any predecessor, had shared his plans months ago with political allies in Westport, a reliably Democratic shoreline community in Fairfield County.

“I have, up till at this moment, been able to avoid it being broadcast across the globe,” he said.

The moment no longer could be avoided once Matthew Mandell, 65, the executive director of the Westport-Wilton Chamber of Commerce and a member of Westport’s representative town meeting, registered as a candidate for the seat.

“He knew this was my last term, like year ago. So it’s not exactly news. There was, like, a 1% chance that there would become a reason for me to run again,” Steinberg said.

Mandell registered as a candidate Wednesday.

The committee Steinberg leads has become a battleground in recent years over the state’s aggressive regulatory posture towards Eversource and Avangrid and the utilities’ animosity towards Marissa P. Gillett during her tenure as the top regulator.

Gillett resigned in September as chair of the Public Utilities Regulatory Authority amid industry and some legislative complaints over her transparency, veracity and leadership style.

One issue was what role she had in producing an opinion piece harshly critical of the utilities that was published by the Connecticut Mirror under the bylines of Steinberg and his co-chair, Sen. Norm Needleman, D-Essex.

Gillett later admitted deleting an exchange of text messages with Steinberg, though both maintained that she did not help write the piece. Needleman and Steinberg both were defenders of Gillett.

Steinberg said Thursday the controversity played no role in his decision to retire after his current two-year term ends in January 2027.

“It’s been a long time. It’ll be 16 years when this year’s done. I think I’ve had a good run between,” Steinberg said. “My wife retired in October. She’s happily retired at home. I’ll be 70 in a few weeks. Seems like the right time.”

Steinberg is no stranger to legislative controversies. He previously was the co-chair of the Public Health Committee as it drafted and eventually passed legislation repealing the religious exemption on school-age vaccinations.