In Albany, he was a leading proponent of criminal justice reform measures passed by Democrats after they won the majority in 2018. He finished fourth last year in the Democratic primary for comptroller.
Ms. Hochul selected Mr. Benjamin to be her lieutenant governor last August, shortly after she became governor after Mr. Cuomo’s resignation. The decision was widely seen as a way for Ms. Hochul, a white moderate from Buffalo, to expand her appeal to nonwhite voters in New York City ahead of this year’s elections.
It is unclear how carefully Ms. Hochul or her advisers vetted Mr. Benjamin before the appointment.
There had already been published reports by The City at the time showing that Mr. Benjamin’s campaign had benefited from apparent straw donations, as well as ethical concerns about his use of campaign funds for a wedding celebration and automobile expenses. (Mr. Benjamin later refunded the suspect contributions and reached an agreement to repay the campaign expenses in question.)
The duties of the lieutenant governor position vary by administration. Mr. Benjamin has kept a brisk schedule of official events in the eight months since taking office, often presiding over the State Senate and representing Ms. Hochul at events in the New York City area. As Ms. Hochul’s experience made clear, the lieutenant governor’s most important function is to step in should the governor resign or die in office.
Mr. Benjamin faces two formidable primary opponents: Diana Reyna, a former New York City councilwoman, and Ana Maria Archila, an activist backed by the left-leaning Working Families Party.
If either were to defeat him and Ms. Hochul still prevails in her race, the governor could find herself on a Democratic ticket in this fall’s general election with a relatively adversarial running mate.
The news of Mr. Benjamin’s arrest spread throughout Harlem’s political community on Tuesday, with many declaring his innocence. Mr. Benjamin, who rose from being the chairman of the Central Harlem community board, was considered a rising star. When Ms. Hochul announced his appointment, she did so on 125th Street in Harlem.
“When this is all over with, it’ll be what I know: Brian did not do anything to break the law,” said Hazel N. Dukes, the president of the New York State chapter of the N.A.A.C.P., and one of Mr. Benjamin’s political mentors.