Posting on Facebook, a spokesman said: “Unfortunately one of our runners collapsed shortly after finishing their run.
"We were so lucky to have people who are medically or first aid trained who stepped straight in and performed CPR.
"The defibrillator was used and the ambulance arrived quickly.”
"Thank you to everyone who helped today, we did everything we could and we are very grateful to you all.
"And thank you to our volunteers who calmly continued with the event.”
The parkrunner is now believe to be in a stable condition at Doncaster Royal Infirmary.
The spokesman concluded: “It is likely that the quick work of those involved and the use of the defibrillator saved his life.
"We send our very best wishes to our parkrunner and hope he makes a full recovery.”