Uesugi Tomosada was a daimyo of Musashi and the last clan head of the Ougigayatsu branch of the Uesugi Clan. Born in 1525, he succeeded his father Uesugi Tomooki as head of the Ougigayatsu-Uesugi Clan upon his father's death in April of 1537.

In order to hold his own against the mighty Houjou Clan, he built a castle (Jindaiji Castle) at Jindai Temple. However, taking advantage of Tomosada's youth, Houjou Ujitsuna attacked and successfully took Kawagoe Castle in July. Tomosada took flight and later made Matsuyama Castle his main stronghold.

In 1541, he reconciled with his long-time enemy Uesugi Norimasa to deal with a common enemy, Houjou Ujiyasu. In 1545, with the cooperation of Imagawa Yoshimoto of Suruga, they along with Ashikaga Haruuji attacked Kawagoe Castle with 80,000 troops (the Battle of Kawagoe Castle). Tomosada died in battle, ending the Ougigayatsu-Uesugi line.