State Comptroller Kevin Lembo stepping down due to health reasons after 11 years. Gov. Lamont to name replacement.

State comptroller Kevin Lembo, a popular Democrat who was once seen as a contender for governor, announced Friday that he is stepping down at the end of the year due to health concerns after 11 years as the state’s chief accountant.

Lembo has been diagnosed with “a serious and debilitating” cardiac condition that has been worsening in intensity and severity, his office said. His medical team is recommending that he should leave office before his term expires in January of 2023.

“It has been the honor of my life to serve the people of Connecticut as state comptroller,” Lembo, a Democrat, said. “Over 10 years ago, voters took a chance on a gay, vegetarian nerd that had never run for office in his life. I’ve worked every day since to represent this office with honesty, integrity, and a focus on the common good. Even now, I love the work that I do and the people I work with. Unfortunately, my health simply won’t allow me to continue to serve.”

“I came into this job believing that Connecticut was capable of great things, and I leave knowing that’s true,’’ Lembo said in a statement Friday announcing his decision. “I’ve never been more certain that Connecticut’s best days lie ahead, and I look forward to seeing them with my friends and neighbors in the best state in nation.”

Gov. Ned Lamont is expected to name a successor soon.

Lembo, 58, was first elected in 2010, and he was among the longest-serving statewide officials currently serving. The comptroller is Connecticut’s chief fiscal watchdog, overseeing the state payroll and keeping a close eye on state employee benefits such as health care. He is the state’s highest-ranking gay official.

Lembo initiated a number of nationally-recognized health care reforms that improved patient outcomes and saved taxpayers hundreds of millions of dollars. His proposal to grow the state’s reserves have helped grow the Rainy Day Fund and the elimination of billions in pension debt. As the former health care advocate, he has long championed health care reform and efforts to lower prescription drug costs.

He has also been a strong advocate of open government, launching websites that have positioned the state as a national leader in financial transparency.

Lembo was dealt high-profile setbacks in enacting legislation to expand state government’s role in health insurance. He clashed repeatedly — and unsuccessfully — with the insurance industry and other business interests who blocked attempts by him and legislative Democrats to establish a so-called public option that would have created a state-sponsored insurance plan for small businesses and nonprofits.

The final blow was delivered in May by Lamont, a fellow Democrat who opposed the public option. The measure was dropped weeks before this year’s legislative session ended.

Lembo’s stewardship of the office won praise from state lawmakers and the highest-level officials who were saddened by his surprise resignation, including Lamont, U.S. Sen. Richard Blumenthal, and U.S. Reps. Rosa DeLauro and John B. Larson.

“Over the last decade, Kevin has transformed that office and thanks to his leadership we now have better government transparency, better health care and a more stable budget,’' said Rep. Sean Scanlon, a Democrat from Guilford. “As his friend, I will deeply miss working with him but I’m happy that he’s prioritizing his health after prioritizing the health of all of Connecticut as a health care advocate for such a long time.”

House Speaker Matt Ritter, a Democrat from Hartford, said Lembo was an early voice for fiscal prudence regarding the state’s need to fund its pension obligations.

“He was one of the first to continue to remind us of that,’' Ritter said. “Every year [since Lembo took office], we have paid 100% at minimum of our pension payment. … If you go back 30, 40 years that was far from the case and that fiscal discipline will be a legacy of his.”

Martin Looney, Senate President Pro Tem, said Lembo has a long record of supporting progressive proposals. “He’s had a superb and extraordinary 11 years advocating for enlightened policy in the health care and insurance areas‚’’ Looney said. “I’m hoping when his health issues are resolved, he’ll be able to return [to public life.]’'

Lembo had been widely mentioned as a possible contender for governor in 2018. Known as a policy wonk, he gained a reputation for being highly skilled in complicated financial matters. The married father of three has embraced his reputation as a fiscal nerd; at one point, his campaign logo featured a pair of clunky black spectacles.

In 2016, Lembo, who sits on the 10-member State Bond Commission, joined Republicans in criticizing a controversial plan to offer up to $22 million in state loans and grants to the world’s largest hedge fund, Westport-based Bridgewater Associates, headed by Greenwich billionaire Ray Dalio. That stance put Lembo directly at odds with the economic agenda of then-Gov. Dannel P. Malloy, a fellow Democrat.

At the time, Lembo characterized his vote not as a gesture of protest but rather a real acknowledgment of Connecticut’s painful fiscal realities at a time of layoffs.

“We have to be willing to say ‘no’ to the CEO of a large company with the same ease that we say ‘no’ to the mom of a disabled child,” he said then. “In no way was this symbolic. It is about a difference of opinion on what our new economic reality demands.”

State Attorney General William Tong, a fellow constitutional officer, said, “Kevin Lembo is one of the most knowledgeable and dedicated policy wonks and leaders I have had the honor to serve with. His fight for transparency and open government has made us all better public servants, and our state government is stronger because of him.’'

“I can only imagine how difficult it is for Kevin to make the decision to step down from a position that he loves and that he energetically campaigned to fill,’' Lamont said. “Throughout his entire public life, Kevin has dedicated himself to looking out for others, and in his time as comptroller, he has been committed to righting the fiscal ship of Connecticut and fighting to implement policies that tame the state’s revenue volatility and bring financial stability. … Kevin refers to himself as a nerd, and sometimes a nerd is exactly what you need.’'

Under state statutes Lamont can name a successor if the legislator is not in session. Lamont said Friday that he would name a successor soon, and then an election would be held for the open seat in November 2022.

Courant staff writer Stephen Singer contributed to this report.

Daniela Altimari can be reached at dnaltimari@courant.com. Christopher Keating can be reached at ckeating@courant.com