Ms. Cabán, 31, has received the backing of Larry Krasner, the Philadelphia district attorney, and Rachael Rollins, Boston’s reform-minded prosecutor, both of whom are already enforcing some of the same policies that Ms. Cabán says she would adopt.

On Wednesday, she picked up the endorsements of two Democratic presidential candidates: Elizabeth Warren and Bernie Sanders.

Ms. Cabán says she would not ask for cash bail for any charges, including violent crimes; is in favor of closing the Rikers Island jail complex but not in favor of the city’s current plan to build new borough-based jails; and says she would not prosecute those arrested on charges of prostitution, nor their customers.

“My goal as a district attorney is to have as few people in jail and as many people in their communities with access to services and support as we can without compromising public safety,” Ms. Cabán said.

The clamor for change in Queens became more acute as residents watched prosecutors in Brooklyn, Manhattan and the Bronx endorse national changes to criminal justice policy.

“Queens is one of the most diverse places in the country but we did not see the progress of the criminal justice system in a direction addressing the issues affecting communities of color,” said Donovan Richards Jr., a Queens councilman who leads the Council Committee on Public Safety.

“When Staten Island is more progressive on some issues than Queens, we have a problem,” he added.

Last year, the Queens district attorney’s office had the second highest percentage of misdemeanor arrests, 45 percent, resulting in a conviction and sentence, behind only Staten Island.