Salvatore Valestra was once the most powerful and prominent gangster in Gotham City, ruling the city's underworld with an iron-fist alongside his chief-lieutenants Chuckie Sol and Buzz Bronski. About a year before Batman first appeared in Gotham, Salvatore loaned money to the businessman Carl Beaumont. Despite promising he could, Carl was unable to pay Valestra back. Not long after Carl's daughter Andrea became engaged to her sweetheart Bruce Wayne, Carl had both of them flee the country to Europe in order to escape Valestra's wrath.
Valestra managed to hunt down Carl however by bribing Beamont's assistant Arthur Reeves into ratting out Carl's location as Arthur was short on the funds he needed to run as Gotham City Councilman. After extracting the information Valestra sent his top hit-man out to kill Carl, a gangster named Jack Napier who was successful in his mission.
Many years later, Valestra lost his grip over Gotham's criminal underworld to new criminals like Rupert Thorne, Penguin and Two-Face. Additionally, his former enforcer Jack Napier now become the Joker. Additionaly, Salvatore began suffering from respiratory problems, due to his smoking.
After Chuckie and Buzz were murdered, apparently by the Batman (in reality by Andrea Beamont under the alias of "The Phantasm"), Valestra became convinced that he would be targeted next. After being refused help from councilman Arthur Reeves, Salvatore hunted down the Joker, tracking him to the abandoned Gotham World's Fair. Joker was impossible to persuade to his side, leading Sal to lash out at the criminal. In retribution, Joker murdered Valestra with his signature Joker Toxin and left the corpse in his apartment as bait for the Phantasm. Valestra's body was presumably destroyed by a blast set up to kill the murderous vigilante.
- It is possible that (similar to Roland Daggett who was based on Max Shreck) Sal Valestra was inspired by the Burtonverse character of Carl Grissom from the 1989 film. Both characters are aging crime-lords that were Gotham's kingpin in their prime and employers of Jack Napier before he became the Joker. Additionally, both Valestra and Grissom are murdered by the criminal, after his tranformation.
- Valestra's first name being Sal is possibly an allusion to the character of Sal Maroni, a prominent Gotham gangster that was responsible for the creation of Two-Face. In The Animated Series, this role was given to Rupert Thorne.
- Valestra is briefly mentioned in the Elseworld story Batman: White Knight, where his gang is one of many taken over by Jack Napier in his political-scheme to make Gotham City a better place.