He has close-cropped graying hair and wears a thin mustache. He has a 1" linear scar at corner of one of his eyes and his left ear was once pierced. His fingernails are described as slightly larger and presenting with a greater curvature.
He typically wears jeans and polo shirts.
He has a condition known as horizontal nystagmus, uncontrollable, involuntary, rapid and repetitive movement of the eyes. He has a previously fractured collar bone.
Harrigan was last seen in Wilmington, Delaware. He has never been heard from again. His siblings reported him missing on April 23, 2005. He has been known to spend time in Lakeland, Florida, and Jacksonville, Florida.