Harry was an assassin and a friendly acquaintance of fellow assassin John Wick.
Little is known about Harry's background, aside from his occupation as a hitman and his subsequent association with the Continental Hotel.
When fellow assassin Ms. Perkins attempts to conduct business on Continental grounds by claiming the bounty on John Wick, Harry helps the latter to restrain the rule-breaking hitwoman and await for judgement from Winston.
When Perkins wakes up, she silently and swiftly breaks free before overwhelming Harry by smothering him with a pillow and killing him with a shot to the head. For violating Continental rules in her actions against both Wick and Harry, Winston later confronts Perkins, callously telling her that her membership to the Continental has been revoked before having his men execute her.
Harry was a kind and friendly man in spite of his work as a hitman. He was also a strict follower of the rules of the Continental Hotel, refusing to allow Perkins proceed with her contract on John Wick within the hotel's grounds.