Yusa Tsugumitsu served as a bushō during the Sengoku and Azuchi-Momoyama periods.  He was a retainer of the Noto-Hatakeyama clan and a leading member of the Hatakeyama Group of Seven – a political organ comprised of senior retainers who conducted the affairs of the clan by council for a period of years.  Tsugumitsu owned territory in the Suzu District of Noto Province.

Tsugumitsu was born as the son of Yusa Fusamitsu.  At his coming-of-age ceremony, he received one of the characters in his name from his lord, Hatakeyama Yoshitsugu, adopting the name of Tsugumitsu.

In 1553, Tsugumitsu vied with Nukui Fusasada (one of the other members of the Hatakeyama Group of Seven) for leadership of the organ, and, at the Battle of Ōtsuki-Ichinomiya, lost to Fusasada and fled to Kaga Province.   In 1555, in a bid to wrest power away from Fusasada, Hatakeyama Yoshitsuna (a sengoku daimyō and the ninth head of the clan) plotted and carried out a plan to assassinate Fusasada whereupon Tsugumitsu returned to the service of the Hatakeyama.  Following the assassination, however, members of the Nukui clan and their allies (the Miyake clan, along with local adherents of the Ikkō sect) fought against Yoshitsuna in the Kōji Rebellion.  Even after a five-year struggle, the rebel forces were unable to oust Yoshitsuna.

Nevertheless, in the eleventh month of 1566, Yoshitsuna and his father, Hatakeyama Yoshitsugu, were finally ousted in a coup d’état orchestrated by Tsugumitsu and Chō Tsugutsura (a brother-in-law of Tsugumitsu who aligned with the Oda).  The retainers backed Hatakeyama Yoshinori (Yoshitsuna’s eldest son) to serve in a puppet administration where the real power was held by them.  This was known as the Political Incident of Eiroku 9.

Tsugumitsu became so autocratic in his governance that, after the sudden death of Yoshinori in 1574, it was questioned whether Yoshinori had been killed by Tsugumitsu.  After the power of Oda Nobunaga reached into Noto, Chō Tsugutsura gained prominence in lieu of Tsugumitsu.  As a result, Tsugumitsu, who sided with the Uesugi clan, temporarily lost his leadership authority.  However, in 1577, at the Second Siege of Nanao Castle, Tsugumitsu colluded with Uesugi Kenshin of Echigo after Kenshin invaded Noto, wiping-out most of Tsugutsura’s family, pledging allegiance to the Uesugi, and taking complete control of the province for himself.

In 1578, after the death of Uesugi Kenshin, the Oda army invaded Noto a second time, whereupon Tsugumitsu and his son, Yusa Morimitsu, surrendered to the Oda.  Nobunaga, however, did not forgive Tsugumitsu for the earlier killing of the Chō family, and had Tsugumitsu and Morimitsu executed.  According to another theory, Tsugumitsu did not surrender and, instead, fled to Nanao Castle, after which his hide-out was discovered by Chō Tsuratatsu and his entire family was then killed.