Admiral Al Calavicci is an Admiral in the Navy who mostly grew up in an orphanage.
Al is Sam's womanizing, cigar-smoking sidekick and best friend, who appears as a hologram that only Sam, animals, young children, and the mentally ill can see and hear. It was revealed in the final episode of Season 2 that his last four of five total marriages failed because he never got over losing his first wife Beth, the only woman he ever loved. She remarried, thinking he had died in Vietnam, whereas he was MIA and held for years in a POW camp.