The gelding, trained by Andrew Balding, struck from the outer of the track to power in-front with just a furlong remaining.
From that point on, King's Lynn began to pull away from the rest of the field and held off a strong finish from Twilight Calls by a head.
The Queen-owned horse has been shortened in price for the King's Stand Stakes at Royal Ascot, and the odds are likely to head further in that direction before June's meeting.
"A really great result. Thrilled for the horse - he is a star!" said Balding, speaking from Goodwood.
"It is all eyes on Royal Ascot, hopefully. Most likely the King's Stand, but it is a conversation we will have nearer the time.
"He obviously is in the Platinum Jubilee and we put him in the Wokingham, just in case things didn't work out today and we needed another avenue, but obviously that won't be the case.
"He (Probert) gave him a great ride. It was excellent."
Jake Warren, representing the Queen, added: "He's run a blinder and he's been a really consistent horse through two, three, four and now five.
"He's in great shape and condition and handled it really well, so it's an amazing result for Her Majesty.
"It's wonderful to have a result like this for her and it's the beginning of an exciting year."