Miller was an agent of the Strategic Scientific Reserve.
Miller, Wilkes and Johnson returned to the Strategic Scientific Reserve New York Office and briefed Agent John Flynn about their failure. That night Miller and a group of agents from the office went for a drink with Flynn.
The next morning Agent Miller was working when he witnessed how Flynn became angry at Peggy Carter for taking a mission. Instead of recieving orders he watched an unsatisfied Flynn tell Carter that she is going to run S.H.I.E.L.D. in Washington, D.C.. and watched her walk away from the office. 
- Strategic Scientific Reserve