Son of one of Uesugi Kenshin's chief vassals, Irobe Katsunaga, master of Hirabayashi Castle. His elder brother Irobe Akinaga became head of the Irobe Clan after their father's death, but due to poor health turned the position over to Nagazane. He became head of the clan in 1576 and served Kenshin in his turn.

After Kenshin's death, he supported Uesugi Kagekatsu in the Otate no Ran and afterwards became one of Kagekatsu's vassals.

He died of illness in Kyoto while enroute to Nagoya Castle by Kagekatsu's command at the start of the Imjin War.