He's both an attorney and a United States Marine. Monday, those two worlds collided for Middlesex County Assistant District Attorney Terence Kiernan.

Kiernan was honored by DA Gerry Leone and Senators Scott Brown and John Kerry at the DA's office on Commerce Way.

Kiernan, of Arlington, joined the Middlesex District Attorney's Office in November of 2010. Shortly after, the captain in the Marine Corps was deployed for training in January of 2011 and a tour in Afghanistan in July 2011.

He was honored for his service with proclamations from the federal senators and Leone.

Kiernan returned to the United States from Afghanistan on Dec. 30. His first day back on the job as an attorney was Monday. Kiernan is assigned to the Malden District Court.