The Flash is a television show that was retroactively added to the Arrowverse. It began on September 20, 1990, and ended on May 18, 1991.
Barry Allen, a forensic scientist working for the Central City police, is struck by lightning and doused in chemicals in his lab. He develops super speed and creates a superhero identity for himself to fight crime: The Flash. Research scientist Dr. Tina McGee works at S.T.A.R. Labs and helps Barry fight crime while trying to understand how his powers are developing. As well as his super heroics, Barry tries to maintain a private life, and tries to keep his superhero identity from his colleagues, his boss Lt. Garfield, and his best friend, Julio Mendez.
- John Wesley Shipp as The Flash (Barry Allen) and Pollux
- Amanda Pays as Dr. Tina McGee
- Alex Désert as Julio Mendez
- Paula Marshall as Iris West
- Vito D'Ambrosio as Tony Bellows
- Biff Manard as Officer Michael Murphy
- Mike Genovese as Lieutenant Warren Garfield
- Richard Belzer as Joe Kline
- Dick Miller as Fosnight
- Gloria Reuben as Sabrina
- Priscilla Pointer as Nora Allen
- Joyce Hyser as Megan Lockhart
- Justine Burnette as Shawn Allen
- Sven-Ole Thorsen as Mutated Carl Tanner, Swede and Omega
- Mark Hamill as The Trickster (James Jesse)
- Michael Nader as Nicholas Pike
- Jason Bernard as Nightshade (Desmond Powell)
- M. Emmet Walsh as Henry Allen
- John Toles-Bay as Michael
- Robert Shayne as Reggie
- Despite the show's short run, it had enough cultural impact that the The Flash had to inherit the main cast.