Scott Hunter, who worked as a bartender at the House of Parliament on Parliament Street, was visiting the area with a friend for the famous horse race.
Louisville police have arrested and charged three people in connection with Hunter's slaying.
They said the shooting happened late Saturday.
Two men and a woman were arrested late Sunday and are facing murder and robbery charges. Among those charged are a brother and sister. Police believe the trio are responsible for as many as nine robberies in the last three days.
Police said Hunter and a friend were walking around 9 p.m. in the Highland Park neighbourhood of Louisville when they were approached and an altercation ensued. Hunter was shot and pronounced dead at the scene. His friend was not hurt.
Hunter worked at the popular downtown Toronto bar for nine years and was well known to both patrons and around the neighbourhood.
The manager at House on Parliament described Hunter as "a great guy."