Walton Monroe Flynn was a mentally-unstable Marine who fell under investigation for allegedly killing an Iraqi businessman that he was protecting at the time. He worked for Citdential, a private security firm.
Flynn came from a broken home with his past similar that of G. Callen's.
When he turned seven, Flynn's father was busted in a drug conspiracy and his mother was a drunk.
During his childhood, Flynn went through several foster homes and opted to join the Marines the day he turned eighteen with the only other option being a street gang.
According to Nate Getz, joining the Marines gave Flynn a place to belong and a structure he'd never had.
He was eventually found innocent of the crime with Citdential's CEO Peter Caldwell being revealed as the true murderer.
- Chris Tardio previously appeared in the original NCIS series in the Season 4 episode, Skeletons (episode).