According to "Roshi Bunkyu Hokokukiji" written by Shinpachi NAGAKURA who was one of the Shinsengumi leaders, Niimi often exhibited disorderly behaviors and broke laws, not listening to convictions of Serizawa and Kondo.
新選組幹部の永倉新八が書き残した『浪士文久報国記事』によると新見は乱暴が甚だしく、法令を犯して芹沢、近藤の説得にも耳を貸さなかったという。