[19] Rollins succeeded John P. Pappas, who was appointed by Governor Charlie Baker to serve as Suffolk County district attorney from September 26, 2018, completing the final months of Daniel F. Conley's 16-year term.

Senator Ted Cruz also criticized her for stating she would not prosecute certain crimes, such as trespassing, breaking and entering, larceny, resisting arrest, wanton or malicious destruction of property, drug possession with intent to distribute, driving with a suspended or revoked license, and several more.

[32] On December 8, 2021, Vice President Kamala Harris cast a tie-breaking vote on the Senate's motion to invoke cloture on, as well as to confirm, Rollins's nomination.

[33] After her confirmation, the United States Marshals Service refused Rollins' request for a full time security detail, assessing that she was at a low risk of actual harm after receiving death threats via email.

[35] In November 2022, the United States Department of Justice's inspector general opened a wide-ranging ethics probe into Rollins' appearance at a Democratic National Committee political fundraiser with First Lady Jill Biden, her travel, and use of her personal cellphone.

According to the report, Rollins tried to influence the outcome of the race to succeed her as Suffolk County District Attorney by "repeatedly attempt[ing] to sabotage" the campaign of the rival (Kevin Hayden) of her favored candidate (Ricardo Arroyo).

[37][38] Another federal watchdog agency, the U.S. Office of Special Counsel, found in its own investigative report that on multiple occasions Rollins violated the Hatch Act, a law that limits political activity by government workers.

"The leak was an extraordinary breach of public trust by a senior government official, which threatens to erode confidence in the integrity of federal law enforcement actions.

[44] As of March 2024, Rollins works as the special projects administrator at Roxbury Community College, reportedly tasked with leading a program for formerly incarcerated people.