Police on patrol in Seacroft were flagged down by one of the victims, who had been shot in the hand, at about 9pm, shortly after a 999 call about the incident.
The other man had suffered pellet injuries to his head.
Det Chief Insp Steve Thomas said: “The scene of the shooting has been identified as Kingsdale Court, off Boggart Hill Drive in Seacroft.
“The injured men are believed to have been sitting in a parked car when the suspect approached and discharged a shotgun into the vehicle, injuring both men.
“This appears to have been a targeted attack but clearly any incident where people are injured as a result of a firearm being discharged is a cause for concern.”
The men, both aged 26, were taken to hospital for treatment.
The man with head injuries was later released from hospital. The other is continuing to receive treatment to his hand.
His injuries are serious but not life threatening.
Det Chief Insp Thomas added: “The circumstances are being fully investigated and officers are mounting increased patrols in the area to reassure the local community.
“I would urgently like to hear from anyone who witnessed the incident or who has any information that could assist the investigation. I believe there will be people in the local community with an awareness of what has been behind this incident but I appreciate they may be reluctant to come forward given the circumstances.
“I would like to assure anyone in this position that any information they provide will be treated in the strictest confidence and their identity will be protected.”
Anyone with any information is asked to contact the homicide and major enquiry team on 101 or Crimestoppers on 0800 555111.