Yoshida beat Canada's Tonya Lynn Verbeek 3-0 2-0 in tonight's final of the 55kg weight category.
Verbeek was looking to add gold to her collection of Olympic silver and bronze medals, but the 34-year-old could not handle Yoshida, who was roared on by a raucous Japanese following at the ExCeL.
A tense opening period was scoreless until 20 seconds from the end when Yoshida picked her opponent up and dumped her off the mat.
The Japanese then shunted Verbeek off the mat in the second period to claim victory.
Japan have now won all three gold medals in women's Wrestling at the Olympics following the victories of Kaori Icho and Hitomi Obara yesterday.
Jackeline Renteria Castillo of Colombia and Azerbaijan's Yuliya Ratkevich claimed the two bronze medals after coming through this evening's repechage.
Yoshida said afterwards: 'It will take some time before I decide whether I will defend my title in Rio (2016 Games).
'I haven't thought about it at the moment. I was so stressed out today, more so than the last two Olympics, because until I came over to England, my condition was not perfect.
'I'm happy I fulfilled my promise to win the gold today.'