Still, Patrick acknowledged doubts about whether his hopeful brand of politics, and relatively low national profile, would have sold well in a noisy and chaotic primary.

“It’s hard to see how you even get noticed in such a big, broad field without being shrill, sensational, or a celebrity — and I’m none of those things and I’m never going to be any of those things,” he said in September, on a podcast hosted by David Axelrod, a former Obama adviser.

Jesse Mermell, Patrick’s spokeswoman during his second term as governor, said his decision shows that unlike some potential candidates who are just being coy when they insist they’re not certain about a presidential run, the former governor was truly debating the pros and cons of a tough national campaign.

“I don’t know there was ever a moment in his mind where this was a done deal,” said Mermell, who campaigned with Patrick in New Jersey for a congressional candidate this fall.

Patrick, 62, would have likely faced difficulties as a candidate. He is less well known than many national figures such as former vice president Joe Biden and Senators Bernie Sanders and Elizabeth Warren.

As governor, he was credited with securing reforms in transportation, education, and ethics, and launching initiatives that stimulated the clean energy and biotechnology industries. But he was criticized for management failures that led to the death of children in the state’s child welfare system, and the breakdown of the state’s health care website and unemployment benefit system.

And Patrick’s business record could have opened him up to attacks.

Since leaving office, he has been a managing director at Bain Capital, the investment firm Democrats vilified when its founder and Patrick’s predecessor as governor, Mitt Romney, ran for president. Patrick also worked for Texaco, Coca-Cola, and other corporate giants.

Just before his decision not to run was first reported by Politico, the Huffington Post published a scathing piece about his association with the subprime mortgage lender Ameriquest, headlined, “Deval Patrick, Foreclosure Mogul.” Patrick served on the company’s board and, as governor, made a controversial call to a Citigroup executive, vouching for Ameriquest when the company was seeking urgent financial assistance from the firm, the Globe reported in 2007.

Patrick’s family life may have also been weighing on him.

His wife, Diane, was hospitalized for depression in 2007, as she reeled from the unrelenting pressure of his first run for governor. And some who know Patrick expressed concern that the indictment of his brother-in-law earlier this year on charges of kidnapping, rape, and assault could have exposed the family to brutal attacks from President Trump.

Mary Anne Marsh, a Democratic strategist, said she assumed personal reasons must have tipped Patrick’s thinking because he would have enjoyed a huge structural advantage by inheriting the Obama operation that ran two successful presidential campaigns.

“It’s got to give anyone else who’s thinking about running not only pause but the need for even more introspection and examination about what it takes to run,” Marsh said.

Others were less sanguine about Patrick’s chances.

Larry Rasky, a longtime Biden hand, said he had a hard time seeing where Patrick would have fit into the crowded field.

“If anything, it’s an early indication of how challenging it’s going to be to find your space on the game board,” he said. “There are a lot of candidates taking up a lot of geography and a lot of demography and a lot of money and you have to ask yourself: Where do you break out? And I assume they came to a conclusion about that.”

In addition to Warren, three other Democrats from Massachusetts are still considered potential presidential candidates: former secretary of state John F. Kerry and Representatives Seth Moulton and Joseph P. Kennedy III.

Patrick’s departure won’t affect Warren’s fortunes because, as a Bain Capital executive, he cuts a very different profile than Warren, a scourge of Wall Street and darling of the left wing of the party, said Kevin Madden, a Republican political consultant and former Romney aide.

“With Patrick’s executive experience and private sector resume, he would have been working from a different starting block than Warren,” he said. And the usual donor tussle between candidates from the same state wouldn’t have applied in this case, either, he said.

“Warren has a national profile and fund-raising base, though, and the folks from the business community weren’t exactly going to be climbing over each other to support Warren.”

Warren’s fund-raising prowess is one of her strengths going into the 2020 primary fray, and she has demonstrated an ability to raise huge sums from small-dollar donors, far more than Patrick.

Warren raised close to $31 million during her 2018 reelection campaign and ended the race with almost $14 million still in the bank.

On the other hand, several polls showed Massachusetts voters more excited about the prospect of Patrick running for president than Warren, though neither earned overwhelming support. In September, 38 percent of Massachusetts voters said Patrick should run, compared with 32 percent who said Warren should.

Patrick made history in 2006 when he became the state’s first black governor, and his inspirational rise from the South Side of Chicago would have figured prominently in his campaign. Many supporters consider him among the party’s finest orators, capable of galvanizing a grass-roots campaign, one room at a time.

Mermell said she got goosebumps when she listened to him deliver an impromptu sermon at predominantly black church in Asbury Park, N.J., this fall.

There, Patrick quoted Scripture to call for more support for health care, gun control, and education, bringing the congregation to its feet. “That makes me disappointed — that the nation is not going to get to experience that over the next two years,” Mermell said.