While attending a masquerade ball, Thomas Wayne, dressed as a "Bat-Man", defeated a group of hoodlums who attempted to hold up the ball while wearing his costume. Thomas Wayne's actions resulted in Lew Moxon being imprisoned.
Becoming one of the inspirations for Bruce Wayne's own Batman outfit, Thomas Wayne's Bat-Man costume is kept amongst the decomissioned Batman and Robin uniforms in the Batcave trophy room.
Simon Hurt, aka Thomas Wayne, predecessor and ancestral relation to the modern Thomas Wayne, wore a variation of the costume while confronting Thomas Wayne's son, Bruce Wayne, and later Richard Grayson.
In an alternate timeline known as Flashpoint, Thomas Wayne survived the mugging, however, his son, Bruce, was killed instead. As a direct result, Thomas became Batman; improving on his Batsuit and creating a casino ring to fund his efforts as his wife, Martha, became the Joker.