The decision to change sides, so to speak, and the transition itself, can both be difficult, the lawyers say. But any challenges with the transition, including learning to generate business, are outweighed by law firms’ desire to hire practitioners with the sort of experience they possess.

The concept of billing hours and rainmaking “is foreign to us—it’s a totally different line of work,” said Matthew Troiano, who last November joined Einhorn, Harris, Ascher, Barbarito & Frost in Denville as counsel to chair the firm’s four-member criminal practice group. A prosecutor since 2006, and practicing at the Morris County Prosecutor’s Office since 2011, Troiano left that office as chief assistant prosecutor.