Officers were called to Crookes Valley Park, where the man’s body was discovered, at around 4pm this afternoon.
A spokeswoman for South Yorkshire Police said the man’s death was not being treated as suspicious and no one else was being sought in connection with the incident.
She added that the crime scene is expected to remain in place until around 9pm.
The cause of death is not known at this stage.
Members of the public told how a police cordon had been set up close to the play area in the park, with one eye witness saying officers were seen carrying out investigations in nearby bushes.