Former Massachusetts governor Deval L. Patrick jumped into the Democratic presidential contest on Thursday, saying he wants to build “a better, more sustainable, more inclusive American Dream” and acknowledging the difficulty his late start creates in achieving that goal.

“I admire and respect the candidates in the Democratic field; they bring a richness of ideas and experience and a depth of character that makes me proud to be a Democrat,” he said in a video released Thursday. “But if the character of the candidates is an issue in every election, this time is about the character of the country. This time is about whether the day after the election, America will keep her promises.

“This time is about more than removing an unpopular and divisive leader, as important as that is, but about delivering instead for you.”

In a morning interview with CBS, Patrick, 63, appeared to knock former vice president Joe Biden as out of touch and Sen. Elizabeth Warren, his home-state senator, as too dug in on her ideas.

The campaign has been caught between “nostalgia” and the desire to return to what existed before President Trump, he said, and “our big idea or no way.”

“Neither of those seizes the moment,” he said.

After registering for the ballot in New Hampshire later Thursday, Patrick plans to head to California, a state that falls early in the primary calendar and has a wealth of delegates.

Patrick on Wednesday was working through a list of people to alert about his decision, said people with knowledge of his plans who discussed them on the condition of anonymity because they hadn’t been announced.

Patrick’s decision, for which he started laying the groundwork Sunday, could further unsettle the Democratic presidential field less than three months before the contest begins with the Iowa caucuses. He entered the race just days after former New York mayor Mike Bloomberg began making his own plans to join the field.

The twin decisions come amid lingering concern, particularly among more moderate Democrats, about the leading centrist candidate, Biden, as well as the rise on the left of Warren. Bloomberg had initially decided not to run because he thought Biden would be too formidable an opponent. Patrick spent several months in 2018 considering a bid, but ultimately decided not to run, citing “the cruelty of our elections process” and its effect on his family.

Patrick has political strengths and an ability to deliver such soaring oratory that President Barack Obama was accused of taking lines from a 2006 speech of his. He became a two-term governor using an uplifting life story and an aspirational political brand, traits that his allies say could serve him well in a presidential campaign.

Patrick called Biden recently to inform him of his decision, in part because Patrick understands that his candidacy will in some ways be viewed as a rejection of Biden, said a person who spoke recently with Patrick. While Biden has often mentioned his eight-year partnership with “Barack,” Patrick also shares a long history with the former president, and their political networks have often intertwined.

Patrick spoke Wednesday night with Warren, whose political rise he helped in 2012 when he defended her against questions about her claims of Native American heritage. Patrick’s entry is already confounding and dividing many Massachusetts Democrats, who will now have two candidates fighting for the nomination. (A third, Rep. Seth Moulton, dropped out of the race earlier in the year.)

On Thursday, Patrick offered only a cursory view of his issue positions, saying on CBS that he favors a public insurance option over Medicare-for-all and indicating that he wants to “smooth” the tax system rather than invoke a wealth tax. He also noted the late timing of his entry.

“This won’t be easy and it shouldn’t be,” he said in his video, “but I’m placing my faith in the people who feel left out and left back, who just want a fair shot at a better future not built by somebody better than you, not built for you but built with you.”

He is likely to face deep scrutiny in the Democratic primary over his corporate ties. He once worked for Texaco and Coca-Cola and served on the board of subprime mortgage lender Ameriquest.

Since leaving office in 2015, he has been a managing director at Bain Capital, a private equity firm that became a target for Democrats in 2012 when Obama was running against Mitt Romney, the Republican presidential nominee who co-founded the company.

A spokesman for Bain did not return several messages asking whether Patrick still remains with the firm. Patrick had been scheduled to speak Wednesday at an investors’ conference in Colorado Springs, but he backed out at the last minute. Bain sent another director instead.

Patrick appeared intent on pushing back against any criticism on that front in his announcement video, recalling growing up on the South Side of Chicago in his grandparents’ “tenement,” sometimes on welfare.

“My grandmother used to tell us we were not poor, just broke, because broke, she said, was temporary,” he said. “I learned to look up, not down, to hope for the best and work for it.”

One major challenge for Patrick is that he has little time to build the kind of grass-roots campaign operation he prized himself on in Massachusetts. He also may not be able to meet the qualification standards needed to get onto the debate stage.

“When I was thinking about it many months ago, one of the questions was: ‘How do you break through in a field this large and this talented without being a celebrity or a sensationalist?’ ” he said on CBS in June. “And I’m none of those things.”

The former governor already has missed filing deadlines for Arkansas and Alabama, which could put him at a significant disadvantage if the race turns into a fight for delegates.

Patrick will focus his campaign closely on New Hampshire, but there, too, he will need to make a case that he brings something new to the crowded field. Two senators from neighboring states, Warren and Bernie Sanders (Vt.), will also be on the ballot.

A New Hampshire poll released by Suffolk University in May 2018 found Patrick in the middle of the pack, at 4 percent.

Patrick, who is African American, is aiming to gain ground among black voters in states such as South Carolina, something that has not been achieved by Democratic Sens. Kamala D. Harris (Calif.) or Cory Booker (N.J.), who also are African American, according to polling. He also replicates others in the field: current and former governors who have struggled to gain traction and other moderates who have been unable to catch fire.

One of the reasons Patrick initially decided not to run was the strain it would put on his family.

“The process is cruel,” he told Boston public radio station WBUR last year. “Every family has its warts, has its issues . . . has things they’d rather keep private, and we do as well.”

His wife, Diane, was hospitalized for depression after a bruising and racially divisive 2006 gubernatorial campaign. She also received a diagnosislast year of Stage 1 uterine cancer but now has a good prognosis. The couple’s two daughters, both in their early 30s, also opposed the race, but are now said to be more amenable.

The rigors of a presidential campaign could also reopen a painful chapter involving Patrick’s sister.

Bernard Sigh, Patrick’s former brother-in-law, was sentenced in June to more than six years in prison after he was convicted of several charges, including the kidnapping and rape of Patrick’s sister.

Patrick in 2014 removed the top two officials at the Massachusetts Sex Offender Registry Board in part because they had tried to force Sigh to register as a sex offender for an earlier conviction in California for raping Patrick’s sister.

Patrick also lacks the financial resources needed for a campaign that will probably stretch into next spring. His campaign advisers have been testing the groundwork for a super PAC as a way to infuse cash into his efforts. But that may also come with political downsides in an environment in which most candidates are building an army of small-dollar donors.

Patrick has spent the past several days trying to recruit a top campaign staff but has been rebuffed by several potential hires. Several of his longtime advisers — who earlier had been prepared to join his campaign — are now working elsewhere.

John Walsh, who helped Patrick’s rise as governor and later served as chairman of the Massachusetts Democratic Party, is running the reelection campaign of Sen. Edward J. Markey (Mass.). Doug Rubin, who was Patrick’s chief of staff and one of his closest advisers, is working for Tom Steyer’s presidential campaign. Bakari Sellers, who was helping plot out Patrick’s campaign a year ago and has significant South Carolina connections, has since backed Harris.

“If you can get unvarnished, vintage Deval Patrick out there to the world, anyone would be crazy to underestimate what that can do,” said one operative in Massachusetts who has worked with Patrick in the past but is not involved with the campaign. “But the landscape is tougher when you come in at this point.”

Rosy Gonzalez Speers, a former Patrick adviser who most recently worked for Andrew Gillum’s gubernatorial bid in Florida, has been one of those advising Patrick. They have talked with several potential campaign managers, according to people knowledgeable about those conversations, but have not announced who might run the operation.

Wesley Lowery contributed to this report.