Scott Rathbone, 21, from Mansfield works as a community first responder (CFR) in his spare time, meaning he attends serious medical emergencies to offer vital help until paramedics arrive.
This can include using a defibrillator on patients whose hearts have stopped.
But the university student was left unable to carry out his voluntary work, and hit with a repair bill of almost £1,000 after his rear window was smashed and one of his tyres was slashed.
The vandals also left deep scratches around the entire bodywork of the Ford Fiesta.
It had been parked outside his home near the John Cockle pub in Mansfield on Thursday.
“I’m angry and upset and it’s frustrating because there are people who need help and I couldn’t respond,” he said.
“I really don’t have any idea who would have done this.
“I was unable to work at the weekend and that’s when we get most of the call outs.
“I had some of the money because I’d just had my grant, but it was meant to be for university books and now I’ve had to fork out for this.”
Scott has been a first responder for just over a year, having been called out to 150 incidents, including seven heart attacks and several stroke emergencies.
“It’s a passion of mine and I absolutely love it,” he said.
“The next time an opportunity opens to become an ambulance technician, I will be applying.”
Scott, who also works part time as a support worker, is now appealing for financial help to help pay for the repairs.
Long-serving responder Gareth Oughton and friend said: “It would be good if someone could help him, it’s such a shame that someone has done this to a young man who has given up his free time to help others.
“He has come on a long way, he has so much enthusiasm and is respected by everyone.”
Anyone willing to offer financial assistance is being asked to contact Nick at the Chad on 01623 450283.