OK, This person is a little tricky to write out but I will do the best I can.

First when I saw him on the show he was the chief Security officer on Babylon 5.

((In 2260, while on patrol in his Starfury, Garibaldi was abducted by a Shadow vessel and didn't reappear until some time later. After his return, Garibaldi was different and began questioning Sheridan's orders. Finally having enough of Sheridan's "second-coming" attitude, Garibaldi resigned and started working as a private investigator on Babylon 5. Later in 2261 he was hired by William Edgars to help move items through Babylon 5 customs. He moved to Mars late in 2261 to further work with Edgars and was almost killed twice in unspecified incidents on Mars. Garibaldi betrayed Sheridan and set a trap for Sheridan to come to Mars, where he was imprisoned and questioned by Earth Force. ))

((Garibaldi later discovered that his resignation, betrayal of Sheridan, and his work for Edgars Industries was in fact controlled by the Psi Cop Bester without his knowledge. This controlling personality was implanted while he was missing from Babylon 5, and was used to determine if a threat against the telepaths existed. After convincing Sheridan and the other members of his inner circle that he was not at fault, Sheridan appointed Garibaldi the leader of covert operations for the new Alliance.))

Information in the yellow brackets came from other sites.