Jimmy Palmer works alongside Donald "Ducky" Mallard as the assistant medical examiner as part of the NCIS crew.
Palmer first showed up as a temporary replacement medical examiner when his predecessor, Gerald Jackson, was injured as a result of a gunshot from a terrorist.
He has a deep affection and respect for Ducky, and to a certain extent has mimicked him by talking to the dead. Although his version of this behaviour is a little more ribald than Ducky's.
When Ducky suffered a heart attack on a beach, Palmer met up with him at hospital. Palmer reluctantly took over Ducky's duties and was relieved when his boss finally recovered and was able to resume his work.
Tony DiNozzo often refers to Palmer as the "autopsy gremlin".
Palmer enjoys telling stale jokes, and becomes nervous and awkward when Gibbs enters the room.
Jimmy is married to Breena Slater. As a result of their inability to conceive, they are hoping to adopt a child.
In NCIS Season 11 Episode 11, he and Breena met up with a prospective birth mother.