Sheriff Steve Tompkins endorses Boston mayoral candidate Michelle Wu

City Councilor and mayoral candidate Michelle Wu (right) received the endorsement of Suffolk County Sheriff Steven W. Tompkins on Tuesday.Pat Greenhouse/Globe Staff

Suffolk County Sheriff Steven W. Tompkins endorsed City Councilor Michelle Wu for Boston’s mayor Tuesday afternoon, a boost of support from a top Black elected official and community leader, and from the law enforcement community.

Tompkins said he has known Wu for nearly a decade, that they worked together to elect Senator Elizabeth Warren, and he cited her “commitment to the communities of Boston and economic justice for all,” according to a release announcing the endorsement.

Tompkins made the announcement at a Wu campaign event outside the Reggie Lewis Center in Roxbury.

“I have seen firsthand the pure devotion to service that she has for the city of Boston and the people and organizations that operate within its borders,” Tompkins said in a statement.

He said she has been a “tireless advocate” for services including more addiction recovery treatment and services for people struggling with mental illness, fair and equitable public transportation, affordable housing, public safety, and access to quality education.

“I am both incredibly proud to be able to give my support to Michelle and supremely confident in her ability to bring this city to its next level of greatness,” he said.

In a statement, Wu cited Tompkins’ shared priorities of offering mental health and economic supports, and other re-entry programs, to help inmates avoid returning to jail once they are released. Tompkins created the “Common Ground Institute,” a vocational training and re-entry program that teaches inmates marketable vocation skills. Tompkins has worked in the sheriff’s department since 2002, and was appointed sheriff by then-Governor Deval Patrick to fill a vacancy in 2013. He was officially elected to the post in 2014.

“Sheriff Tompkins has worked for years to provide educational opportunities, economic development and re-entry support for formerly incarcerated community members,” Wu said in a statement. “I look forward to partnering with him in City Hall to ensure all of our neighborhoods have the resources they need to be safe, supported, and healthy.”

The boost of support, with two weeks to go until the Sept. 14 preliminary election, could be critical, as candidates on the race are banking on a high voter turnout, particularly from Black communities, in their path to victory. A recent Emerson College/7News poll shows that 25 percent of the electorate remains undecided, and that Black Bostonians are more likely to back the two Black women in the race, with Acting Mayor Kim Janey garnering 31 percent of support and City Councilor Andrea Campbell getting 24 percent.

In an interview Tuesday, Tompkins said he knows all of the candidates well, and that he recognized the significance of supporting candidates seeking to make history as Boston’s first elected Black mayor. But, he said, he weighed that significance against his personal work with Wu, who “I feel passionately about, that can get the job done, and who I know exceedingly well.”

“At the end of the day, that goes to the top,” he said, “Michelle is family to me … I can only pick one, so I decided to go with family.”