 He was in 2 UDR's C (Lurgan) Company before it became C Company 11th Battalion Ulster Defence Regiment (C Coy, 11 UDR) in 1972.He served as a permanent staff instructor (PSI), holding the rank of sergeant, although he was for a time weapons instructor at 2 UDR's base in Gough Barracks in Armagh.According to David McKittrick and UDR historian John Potter, Hanna was dismissed from the UDR after serving two years as a sergeant "for UVF activity", however, authors Malcolm Sutton and Martin Dillon suggested he was still a member of the regiment at the time of his death.