Whiteside famously scored the only goal to clinch FA Cup success for United against Everton in the 1985 final.
The shirt he wore had an estimate of £4,000-£6,000 but when the hammer fell it had gone for £23,000.
"This will go a long way to subsidise my pension that I never really had when I was a player," said the 55-year-old.
He was earning just £250 a week at Old Trafford at the time and was forced to retire at 26 because of a knee injury after scoring 68 goals in 278 games for United and Everton.
After Wednesday's auction, which far exceeded estimates to raise £194,680, Whiteside added that he was "really delighted with the outcome".
Whiteside's winners' medal from the Wembley final in 1985 topped the money list by fetching £30,000 while his 1983 FA Cup winners' medal was auctioned for £24,000 - at 18 he became the youngest ever goalscorer in a final in the victory over Brighton.
The Northern Ireland shirt he wore against Yugoslavia at the 1982 World Cup went for £18,000 - £10,000 higher than the estimate.