Born in 1561 as the fourth son of Murakami Michiyasu, head of the Kurushima Murakami clan, whose mother was a daughter of the ruling Iyo constable Kono Michinao. When his father died in 1567, he inherited the lordship of Kurushima Castle at just seven years old. In 1582, courted by Hashiba Hideyoshi, he broke with his overlords the Kono and Mori clans to defect to the Oda-Toyotomi side, losing his base at Kurushima Castle in the process. Hideyoshi is said to have prized him greatly, repeatedly calling him by name and having him change his surname from Murakami to Kurushima. Distinguishing himself as vanguard commander in Hideyoshi's 1585 conquest of Shikoku, he was granted 14,000 koku in Kazahaya District, Iyo, and became a daimyo in his own right. In 1597, during the Keicho Campaign in Korea, he led naval forces and served as vanguard at the Battle of Myeongnyang on September 16, where his fleet was overwhelmed by the Korean navy exploiting the strait's treacherous currents. He died in battle at age 37.

A pragmatist who read the shifting tides of power, choosing the rising Toyotomi over his own overlords despite the risk. Having survived becoming clan head at age seven, he showed the boldness to break from the Kono and Mori — and met a fittingly warrior's end leading the vanguard at sea.

The ruins of Kurushima Castle, base of the Murakami pirates (Murakami Kaizoku), are a National Historic Site, and in 2016 were recognized as a Japan Heritage component of 'Japan's Greatest Pirates: The Murakami Kaizoku of Kurushima.' His descendants continued as lords of Yoshida domain in Iyo, carrying the memory of the Kurushima navy into later ages.