Daihoji Yoshioki was born as the younger brother of Daihoji Yoshiuji, 17th head of the Daihoji clan, sengoku daimyo of the Shonai region. Known as "Maruoka Hyogo no Kami," he made Maruoka Castle in Kushibiki district his seat. His brother Yoshiuji advanced the unification of Shonai in 1571 by destroying his retainer Tosabayashi Zento, but when Yoshiuji was forced to commit suicide by a retainer revolt in 1583, Yoshioki inherited the headship as 18th head of the Daihoji clan and moved his base to Oura Castle. He sought to maintain control of Shonai with the backing of Uesugi Kagekatsu, but in 1587 was driven to suicide at Oura Castle by a revolt led by his senior retainer Tozenji Yoshinaga, who had allied with Mogami Yoshiaki. He was 34.

A daimyo of tragic fortune who inherited the headship amid the turmoil of his brother's sudden death and sought to preserve Shonai, only to meet a violent end through his retainers' betrayal.

The Daihoji clan reached the height of its rule over Shonai during Yoshioki's time, from Maruoka to Oura Castle, but after his death Shonai became a battleground between the Mogami and Uesugi, effectively ending the Daihoji clan's history as an independent daimyo house.