Murai Sadanari served as a bushō during the Azuchi-Momoyama period.  He had the common name of Sakuemon-no-jō.  He also used the other name of Sadamori.

Sadanari was born as the eldest son of Murai Sadakatsu, the Kyōto shoshidai, or official in charge of the Board of Retainers, an office in the Muromachi bakufu to guard the shōgun and give judgment on criminals in Kyōto for the Oda administration.

Similar to his father, Sadanari served Nobunaga, becoming a member of the umamawari, or cavalry soldiers.  In 1569, Sadanari participated in an assault on Ōkawachi Castle in Ise Province, indicating that he served as a retainer from the middle of the Nobunaga era.  From the time that his father, Sadakatsu, became the Kyōto shoshidai, Sadanari served as a deputy but came into conflict with a family member named Murai Seizō and, at the end of 1578, was ousted.

In 1581, at the Kyōto Mounted Horse Parade, Sadanari attended as a senior retainer of the Oda clan.  In this same year, his father entered the priesthood so he inherited the headship of the clan.  On 6/2 of Tenshō 10 (1582), Akechi Mitsuhide launched a coup d’état against Nobunaga in an event known as the Honnō Temple Incident.  During the event, Sadanari, together with his father and younger brother, Murai Seiji, rushed to the Myōkaku Temple to inform Nobunaga’s eldest son, Oda Nobutada, of the attack.  Sadanari and the others then holed-up in Nijō palace to fight against the Akechi forces, but were killed in action.