Utsunomiya Okitsuna served as a bushō during the Sengoku period.  Okitsuna was the nineteenth head of the Shimotsuke-Utsunomiya clan.

There are three primary theories concerning the origins of Okitsuna, as follows:

First, the traditional theory (based on numerous sources) is that Okitsuna was the second son of Utsunomiya Masatsuna (the sixteenth head of the Shimotsuke-Utsunomiya clan), the father of Utsunomiya Hisatsuna (Toshitsuna), and he died at the age of sixty-one.

Second, according to the genealogy of the Utsunomiya clan, Utsunomiya Tadatsuna, Hisatsuna, and Okitsuna were siblings (the sons of Utsunomiya Shigetsuna).  This is substantiated by a letter in 1524 from Ashikaga Takamoto (the Koga kubō) to Osanami Mikawa-no-kami (a member of the Kazusa-Takeda clan) which refers to the backing of a younger proxy for Tadatsuna.  After Tadatsuna was expelled as the head of the clan, there are no sources indicating that an individual received backing other than Okitsuna, indicating that Okitsuna was in his youth at this time.  It is said that he was initially adopted by the Haga clan and inherited the headship, but there are theories disavowing this as well.

Third, there is a theory that he was the son of Tadatsuna.  This view is supported by several sources.  In the case of the second and third theories, he died at the age of twenty-three.

According to the death registry at the Nikkōsan-Rinnō Temple, Okitsuna died at the age of sixty-one and Buddhist memorial services were held based on this age.  In records of the Nasu family, Okitsuna was the younger brother of Shigetsuna.  In the genealogy of the Akita-Shionoya family, he was the fourth son of Utsunomiya Takatsuna.  Based, however, on the various records supporting the theory that he was the second son of Masatsuna, this remains the most compelling theory.  Nevertheless, there remains a lack of dispositive evidence that he was the son of either Masatsuna, Shigetsuna, or Tadatsuna, so the debate continues.

In 1523, Tadatsuna was expelled from Utsunomiya Castle in the wake of his defeat to Yūki Masatomo at the Battle of Saruyama.  Dissatisfied with the Tadatsuna’s oppressive rule, a young Okitsuna obtained the backing of Haga Takatsune and other retainers opposed to Tadatsuna.  These events are known as the Daiei Discord.  Initially, he served as their puppet leader.  Later, after Okitsuna matured and began to operate independently, he came into conflict with Takatsune and Mibu Tsunafusa.  After losing in this power struggle with his senior retainers, Okitsuna was forced into retirement and later took his own life.