Scientist Kirk Langstrom worked as a Zoologist at the Gotham City Zoo, and experimented with bat mutagen to create a serum to replicate the creatures' long life under the tutelage of his father-in-law, Dr. Marsh. Dr. Marsh was obsessed with the idea that humanity would not be able to survive mass extinction, whereas bats would, and devleoped a serum that would give people bat-like abilities to survive. However, Dr. Marsh was unwilling to test the serum, whereas his son-in-law Dr. Langstrom was. After he tested the serum on himself, Langstrom became the vicious Man-Bat. Though Batman eventually cured Langstrom, the creature made future appearances.
Dr. Kirk Langstrom was a zoologist at the Gotham City Zoo. He first appeared in "On Leather Wings", where he stole a serum at a chemical lab. Langstrom also had a wife named Francine. One night, Langstrom drank the serum, when Batman arrived to question him - and revealed himself as the thief of the serum from the chemical labs. Langstrom transformed into a half-man, half-bat creature, and turned on Batman. Francine arrived at the lab and discovered that the creature was her husband. Langstrom was cured and returned to his wife. Langstrom next appeared in "Tyger, Tyger" where he analyzed the chemical that Dr. Emile Dorian had used in his experiments.
In the episode, "Terror in the Sky", Langstrom had a dream that he transformed into Man-Bat, and began to commit crimes. Then, Langstrom was awakened, just to find the remains of the fruit and scratches from a rag. Then, as Francine decided to go to another city, due to Langstrom's inability to control the power of Man-Bat, he then discovered that the other Man-Bat turned out to be Francine herself, who was accidentally exposed to an alternate Ban-Bat serum. In the end, Batman cured Francine, and she returned to her husband.
When Batman: The Animated Series was revamped into The New Batman Adventures, Langstrom as Man-Bat never appeared in the new show. However, Langstrom did make a cameo in Bruce Wayne's wedding in the episode "Chemistry", so he appeared to be finally cured. In the comic Batman: Gotham Adventures, which was based on the show, Man-Bat made an appearance in issue #18.
In the Justice League Unlimited episode "The Doomsday Sanction", Professor Milo mentioned that Dr. Langstrom's research had proven useful to his experiments splicing together human and animal DNA for the Cadmus Project. That ended with a disaster when a mutated warthog was mentioned to have destroyed his lab.