Tsunade Senju was Konoha’s Fifth Hokage. This title was passed on to her after Hiruzen, the Third Hokage passed away. However, she was not the only one who could’ve received the title.
I’ve made a list of all 5 characters who I think could’ve been the Fifth Hokage.
Jiraiya was one of Konoha’s legendary Sannin. He was also a child prodigy, who graduated the academy at 6! He also turned out to be a great shinobi, and thus was also offered the position of Hokage two times. However, he was never interested in becoming the Hokage. Otherwise, he would’ve been one of the strongest that we ever saw.