Ex-councillor Margaret Sheard litter-picks at the multi-use games area (MUGA) at the park on Silverdale Drive, Monk Bretton, each week but has found fire damage and rubbish.
A large patch of tarmac in the MUGA was burned at some point last week, raising serious fire safety concerns.
The week before, a bench in the park had been another target of arson.
“I’ve lived in Monk Bretton for 50 years, it’s a place that I really want to see looking well, so this is just completely unaccceptable,” Margaret said.
“It’s absolutely digusting.
“We worked hard to get that MUGA so to see that is just disgusting.
“There were well over 100 cans and the fire must have been big to burn the tarmac.”
South Yorkshire Fire and Rescue watch manager, Craig Huxley, told the Chronicle the area is on officers’ radars, as well as the local policing team’s patrol list.
“Deliberate fire-setting is reckless, dangerous and, quite simply, not acceptable.
“Not only does it tie up our crews - potentially slowing their response to another serious incident - but it causes significant damage to local areas.
“Even small fires risk spreading and growing into something much bigger.
“Tell us what you know, however big or small, and help us stamp out arson for good.”