Hennessy currently is a federal prosecutor who serves as chief of the Worcester branch of the U.S. attorney’s office. The cases he has tried in that office include violations of tax, gun, drug and child protection laws.
When appointed, Hennessy will sit in Worcester. His selection is subject to a required background investigation.
The vacancy was created when Hillman was appointed as a U.S. District judge.
The 58-year-old Hennessy was also an acting deputy assistant attorney general in the criminal division in Washington, D.C.
Hennessy also has served as an assistant U.S. attorney in the Eastern District of New York.