Though the Emperor Tenmu applied Tenno Sippe Politics (pro-imperial family politics) without minister's posts, Shima promoted to Udaijin (Minister of the right) which had not been occupied since NAKATOMI no Kane who was punished in the Jinshin War when the Emperor Tenmu died and his empress, Uno no Sarara no Himemiko ascended the throne as the Emperor Jito, ruling without official accession to the Chrysanthemum Throne in 690.
天武天皇は大臣を置かない、皇親政治を執っていたが、天皇が崩御し、690年（持統天皇4年）に皇后の鸕野讚良皇女が称制を経て持統天皇として即位すると、嶋も壬申の乱で罰せられた中臣金以来空職となっていた右大臣に出世する。