Before the Joker's attack on Superman that would change the course of history, Leonard Snart and his sister Lisa were thieves in Central City who commonly found themselves fighting the city's hero the Flash. Contacting the Flash's other villains, "Captain Cold" as he came to be known lead a team of the Flash's rogues against him but, ultimately, were always defeated.
After the Joker caused Superman to accidentally kill his wife Lois Lane and destroy Metropolis, the man of steel went insane, killing the Joker and initiating a new regime to combat crime.
Soon after the destruction of Metropolis, Captain Cold was confronted by members of the Justice League, looking for information regarding Mirror Master. The Flash, in his interrogation, causes Snart's cold gun to misfire onto the villain himself, thus forcing Snart to give up Mirror Master's location in Keystone City. 
At some point after this interaction with the Flash, Captain Cold was arrested and sent to a super prison under the sea created by the Regime, where he was held until the fourth year of Superman's rule. At that time, Cold and every other villain in the prison was freed by Plastic Man, looking to rescue his son, and Snart went into hiding. 
Driven by revenge for the executions of his sister Lisa and the other Rogues during Superman's rule, Captain Cold allied with Gorilla Grodd's Society. He thought he was working with the other criminals to take over the world in Superman's absence. However, Grodd's silent partner and true mastermind behind the Society, whose identity was initially only known to him, was Brainiac, who intended to abduct cities of Earth to study and then destroy the planet.
Captain Cold was sent on several missions to subdue the heroes that threatened the Society's plan, holding a grudge against former Regime members, especially the Flash. However, after the Society discovered Brainiac's true intentions of destroying the planet, the team disbanded, and Captain Cold had gone his separate way.
Possible Post-Brainiac Epilogue
This section of history takes place in a timeline outside that of normal Injustice: Gods Among Us history. Information here does not reflect the true history of neither the Injustice: Gods Among Us universe nor the Injustice: The Regime universe, and should not be seen as relevant to future sequels or comic adaptations.
"Going after the Regime was one thing. But destroy the planet for Brainiac? You really thought I'd go through with it, Grodd? Really?! [BLEEP] you!
Sorry it's been awhile, sis. I know I've always got an excuse but, this time, I finally figured out the right way to honor your memory. I know what you're thinking - 'old Lenny sold out'. So what? I'm making sure the Regime and Brainiac never happen again. Even buried the hatchet with old Scarlet Speedster. Ironically or whatever, he's the best partner I ever had. 'Sides you, sis."
- Hand-to-Hand Combat (Basic)
- Leadership: He is a natural leader and has lead the Rogues through countless years of criminality. He's also led a splinter group of villains during a hellish event.
- Tactical Analysis: He also has a very tactical mind and his own personal sense of honor.
- 12 Appearances of Leonard Snart (Injustice: The Regime)
- 5 Images featuring Leonard Snart (Injustice: The Regime)
- 2 Quotations by or about Leonard Snart (Injustice: The Regime)
- Character Gallery: Leonard Snart (Injustice: The Regime)
Suicide Squad member
Secret Society of Super-Villains member