Okabe Noritsuna served as a bushō from the Sengoku to early Edo periods. His common name was Daigaku-no-suke.
Noritsuna served Asahina Nobuoki, a retainer of the Imagawa clan, the sengoku daimyō of Suruga Province, but later left this role to serve other daimyō.
In 1614, during the Winter Campaign of the Siege of Ōsaka, Noritsuna entered Ōsaka Castle and joined a unit led by Ōno Harunaga. In 1615, during the Summer Campaign, he joined forces with Ban Naoyuki and Tannowa Shigemasa to fight against the army of Asano Nagaakira at the Battle of Kashii, but was defeated. Although Noritsuna committed to kill himself, he was stopped by Mōri Katsunaga.
After the fall of Ōsaka Castle, he safely fled, changed his name to Kiseian, and lived a secluded life.