Massachusetts House Speaker Robert DeLeo is negotiating a job at Northeastern University, a move that would end his 12 year tenure as perhaps the most powerful figure in state government.

The news, revealed in an ethics dislosure filed with the House Clerk on Friday, ends days of intense speculation on Beacon Hill.

DeLeo is the longest-serving speaker in state history.

In over five full terms, DeLeo oversaw an incremental liberal agenda while resisting most broad tax increases and keeping an unwavering grip on power. To achieve that, he worked through his chosen — and extremely loyal — team of chairs and floor leaders to generate broad consensus within the House.

His likely successor is Majority Leader Ronald Mariano, a 74-year old from Quincy who's been in the House for just under 30 years and is a close DeLeo ally. Mariano supporters who spoke to GBH News said he has more than enough votes to be elected speaker.

“If Speaker DeLeo resigns, I will be a candidate for speaker of the Massachusetts House of Representatives," Mariano said in a press statement distributed Friday afternoon. "I believe I have earned the trust and confidence of my colleagues and that I have gained their support to lead the House forward."

Gov. Charlie Baker cautioned lawmakers not to let a transition of power in the House distract from pressing legislative issues that have only days to pass before the end of the session.

"I hope that in the midst of whatever it is that's going to happen on this issue here, that agenda, which is still very much alive, real and needs to get done sometime between now and Jan. 4 ... gets done," Baker said at his daily COVID-19 press conference.

In a statement circulated to the press Friday, a spokesperson for Northeastern University wrote that the school is "looking forward to discussing with Speaker DeLeo opportunities to welcome him back to his alma mater."

Like DeLeo, Mariano is seen as a moderate Democrat. When it comes to abortion access, for example, Planned Parenthood of Massachusetts considers him an ally.

The party's left wing, however, takes a dimmer view. Progressive Massachusetts gives Mariano a "D" when it comes to supporting the agenda shared by most left-wing activists.

The unwavering anti-tax Massachusetts Fiscal Alliance rated Mariano's voting record for last session at 2%. That's a bit lower than the average for most Democrats and is identical to DeLeo's score.

Mariano said that in the final days of the Legislature's 2019 – 2020 session, "the House must remain focused on rejecting Governor Baker’s efforts to weaken a woman’s right to choose and to dilute our police reform legislation," hitting on two of the most pressing matters lawmakers say they intend to wrap up before the new year.

Baker said he and his team know Mariano from years of working with him on health care policy.

"Rob Mariano, for all intents and purposes, is probably the the key voice in the House on health care issues, and we spent a lot of time with him talking about health care over the last five years," Baker said.

DeLeo rose to power in 2009 after former Speaker Sal DiMasi resigned amid an ethics investigation and conviction on corruption charges for which he served five years in federal prison.

DeLeo released the following statement Friday:

“Today I filed a disclosure letter with the House Clerk and the Massachusetts State Ethics Commission to disclose that I intend to begin negotiating prospective employment opportunities with Northeastern University. As of today, I have not personally had any discussions with anyone from Northeastern University relative to any possible employment opportunities.

“On December 16, 2020, I requested that my personal legal counsel contact the Massachusetts State Ethics Commission to discuss my status and to ensure compliance with the requirements of the Conflict of Interest Law. Although, based on my current status, a disclosure is not currently required I have nevertheless elected to disclose my intention to begin negotiating prospective employment opportunities with Northeastern University out of an abundance of caution.

“As such, and while I know of no matter, particular matter or general legislation presently before me in my official role that would affect Northeastern University, I filed the disclosure to dispel any appearance of conflict pursuant to G.L. c. 268A, s. 23(b)(3).”