The 19-year-old - who was competing for Great Britain juniors in the Bauhaus Gala in Mannheim, Germany - is now ranked first in the UK, second in Europe and 16th in the world for his age group.
He won the 200m with a time of 20.76 which was more than half a second faster than his previous best.
He has now taken 0.95 seconds off his personal best during the 2019 season while he is the second fastest Yorkshire runner ever after Thomas Somers in 2014.
Ferguson said: “All the top under 20s in Europe were there so to win it was great.
“To improve your PB by half a second is very rare.
“I was hoping for 21.1 because that was the qualifying time for the European Juniors. My coach thought I might have 20.9 in me.
“But when 20.76 came up on the screen I just stood there for a few seconds because I couldn’t process it. Then I celebrated and it was a very good feeling.
“Nobody expected me to run that fast.
“It was only my fourth 200m of the outdoor season so there is plenty more to come.”
Joe - who also claimed another gold with the GB Juniors who won the 4x100m relay with 40.04 - has now qualified for the European Junior Championships in Sweden later this month.
He said: “It’s the biggest event I will have been to.
“Before this week, I was hoping to get a medal but now realistically I will be the favourite so gold has to the aim.
“I will just focus on getting through the rounds and getting a good lane for the final.”
Ferguson’s time in Germany puts him seventh in the UK senior rankings and is 0.35 seconds outside the qualifying time for the World Championships in Qatar in September and October.
He said: “I’m not getting carried away.
“I’ve said before that I want to get to the very top level, and that’s what I train for.
“But I am just taking it one step at a time and focusing on my next event.
“I am still very young and have a lot to work on but things are going well at the moment so I am very happy.”