The 25-year-old jumped 15.15 metres - the only contestant to break the 15m barrier - to walk off with the pounds 31,000 first prize.
The event did not start well for Hansen, with her first two efforts being no-jumps, but her fifth-round leap not only extended her British record by 21cm, but also set a grand prix record.
The success came as some consolation for Hansen after her poor performance in Athens last month in the World Championships. A back injury there put paid to her chances as she struggled into fifth place after being the leading qualifier.
At Fukuoka, Denmark's Wilson Kipketer and Germany's Astrid Kumbernuss clinched the overall men's and women's titles but the crowd saved its applause for Sergei Bubka who came close to breaking his own world record.
Kipketer easily won the 800 metres in 1min 42.98 sec to take the overall grand prix title, awarded to the athlete who earns the most points from the grand prix season. Kumbernuss took the women's title after winning the shot put with a throw of 20.95 metres. Both took home pounds 160,000.
While Kipketer was not thinking about a world record, Bubka said he was after he won the pole vault with a height of 6.05 metres. "I missed a good chance tonight." he said. Bubka, who last set the record with a clearance of 6.14 metres in Sestriere, Italy, in July 1994, made three attempts at 6.15.
Great North hope, page 13