As the Ōtomo were one of the major clans of Kyūshū, along with the Shōni and the Shimazu, they had a central role in organizing efforts against the Mongol invasions of Japan in 1274 and 1281.

At the time of 21st generation Yoshishige, the Ōtomo clan reached its zenith by expanding its power to Hizen, Higo, and Chikuzen Provinces.

[2] At its zenith, the Ōtomo clan ruled six provinces (Buzen, Bungo, Hizen, Higo, Chikuzen and Chikugo) and two half-provinces (Hyūga and Iyo).

Xavier and other Jesuit missionaries would return to Kyūshū, traveling and proselytizing; the Ōtomo were always well-disposed towards them, and they saw some success in Bungo as a result, converting many Japanese to Christianity.

Otomo is a playable nation in the grand strategy games Europa Universalis IV, Sengoku as well as in Total War: Shogun 2.