Firestorm made his first appearance in 1978's Firestorm, The Nuclear Man #1 in which the super being was the merged form of high school student Ronnie Raymond and Professor Martin Stein. He is basically an alchemist able to transmute inorganic matter from one substance to another and he has quite an impressive look.
In 1984, the Ronnie Raymond and Doc Stein Firestorm got his onscreen break in Super Friends: The Legendary Super Powers Show in which he joined the Justice League as their latest recruit.
Firestorm continued as a team member during the final incarnation of the Super Friends, The Super Powers Team: Galactic Guardians along with newcomer Cyborg. During the final series, aside from his heroic acts, Firestorm nearly contributed to the death of Superman. Oops.
Firestorm returned over 25 years later in Batman: The Brave and the Bold. In this version, it was smart teen Jason Rusch controlling Firestorm with Coach Ronnie Raymond in his head.
Just a couple of weeks after his debut on Brave and the Bold, Jason Rusch briefly returned as Firestorm in Justice League: Crisis on Two Earths though it was unclear in this version who was the second identity merged with Jason. Tragically, Firestorm has only appeared in these three shows, but hopefully its just a matter of time before he gets the exposure he deserves.