He was incorporated in the former Edo bakufu army (the army of Japanese feudal government headed by a shogun), together with several Shinsengumi members, such as Toshizo HIJIKATA and Kai SHIMADA, and fought in a series of battles, from the Battle of Utsunomiya and Battle of Nikkoguchi to the Aizu War (it is said that Nakajima carried Seishin OSHIMA, a member of Shogitai (a group of former Tokugawa retainers opposed to the Meiji government who fought in the Battle of Ueno) who was seriously injured in the Aizu War, to an aid station).
土方歳三や島田魁ら数名の新選組隊士らと共に、大鳥圭介ら旧幕府軍と合流して宇都宮の戦い・日光口の戦い・会津戦争に転戦（中島は、会津戦争で重傷を負った彰義隊隊士大島清慎を救護所まで運んだと言う）。