In the day’s morning session, double Paralympic silver medallist Reid jumped 5.40m for her first global title.
Stef, who lost her right foot in a boating accident as a teenager, had finished as runner-up at both London 2012 and Rio 2016 and has previously won 200m bronze at both the Paralympics and World Championships.
“It’s so satisfying. It’s been a long time coming,” she told BBC Radio 5 live.
In the evening session, Richard Whitehead defended his T42 200m title winning gold; billed as one of the main attractions at the London Stadium – the same venue in which he won 2012 Paralympic gold.
He is now a four-time world champion, as well as a two-time Paralympic champion, and is still to compete in the 100m on Monday, an event he has never won at the Paralympics or Worlds.