- "It's complex. This is not just her. Everybody's disappearing. There's this new law where if you're a bad enough bad guy, they stamp terrorist on your jacket. They send you to this swamp in Louisiana. A black site. That's where she is. So what are we doing?"
- ―Jonny Frost to Joker[src]
Working for Joker
Jonny Frost had been working for Joker sometime before 2015. He was present when Joker broke out of Arkham Asylum, holding down Harley Quinn as Joker electrocuted her. He later appears as Joker's body guard at a strip club. He is approached by Monster T who wanted to meet with the Joker. Frost tells him to "Sit down and have a drink." While Monster T and Joker talk, Frost is seen watching with a cold interest.
Tracking Harley Quinn
After Harley Quinn was captured by Batman, Joker went into mourning and painted a black line around his mouth. Under Jokers' orders, Frost was able to discover that Harley and several other prominent Gotham criminals had been taken to a black site, Belle Reve. After telling the Joker this, he is told to bring the car out for a drive. Frost and Joker go to a casino that Belle Reve guard Griggs frequented. They pay off the casino manager, who brings Griggs to them for Joker to interrogate. Frost and Joker learn from him that Harley has been inducted into Task Force X: a team comprised of super villains who go on Black Ops missions for the government. They also learn that members are injected with Nano-Bomb implants to control them.
Assaulting Van Criss Laboratories
Frost accompanies Joker and the rest of his gang to Van Criss Laboratories, a branch of Wayne Industries that manufactured the nano-bombs. While Joker's Gang assault the lab, murdering numerous employees, Frost guides his boss to Dr. Van Criss. He startles the doctor by firing three gunshots into the lab window. Joker is able to blackmail Criss into working with them when he shows him a live feed of his wife being tortured. To ensure that he doesn't rebel, the Joker implants one of his own Nano-Bombs into Criss' neck.
- "Boss, we've got a problem!"
- ―Jonny Frost, just before Savior 10 crashes[src]
Frost, Joker, and Van Criss are able to capture a military helicopter named Savior 10, which was to be used to rescue Amanda Waller. Rick Flag and Task Force X wait for the helicopter, Edwards repeatedly asks for contact. When there is no response, Flag realizes that Savior 10 has been hijacked and informs his crew to take down the bird. Jonny Frost and Joker open fire on Flag and Task Force X while Dr. Van Criss disables Harley Quinn's neck bomb. With Harley free, Joker sends her an SMS telling her to come immediately to the helicopter. Deadshot warns Harley not to go but she happily gets up and starts walking to the helicopter. Frost continues firing while Joker spots Harley and throws a rope out for her to hang on and climb up. Harley jumps onto the rope and is reunited with Joker. However, Frost informs Joker that Savior 10 has been hit. Joker tells Harley then it's just him and her, however, Harley slips out of the helicopter and lands on rooftop below. Savior 10 loses control and crashes into the city. Though Joker survived the crash through unknown means, Frost and everyone else aboard the helicopter were ultimately killed in the ensuing explosion.
Frost is shown to be incredibly loyal to the Joker. He carries out orders for his deranged boss without question, attacking the defenseless psychiatrist Harleen Quinzel and countless scientists. He doesn't show any concern for human life; he is willing to murder anyone that his boss wants dead. He watches his boss' meeting with Monster T with great curiosity, interested to see its outcome. He warranted no reaction when the latter was killed. He has a dark sense of humor, as evidenced by his sarcastic and snarky comments during Griggs's interrogation.
- Joker's gang
- Van Criss † - unwilling ally
- Griggs - unwilling ally
- Amanda Waller
- Task Force X
- United States Armed Forces
- In the Joker graphic novel, Jonny Frost was a low-ranking thug who becomes the Joker's chauffeur and witnesses many of the Joker's most hideous criminal acts. He ultimately loses his life when the Joker shoots him in the chin and lets him fall into a river to bleed there.
- Its worth noting that Frost is the second person non-background character shown to be completely loyal and unquestioning to the Joker in any media, following Harley Quinn herself.
- The position of Jonny Frost as Joker's first lieutenant is a reference to the character Robert "Bob" Hawkins, aka Bob the Goon, from the 1989 film Batman.