Emperor Heizei
In 778, Mamichi was appointed as an in the Ministry of the Center. In 783, he was conferred the rank of . In this period, he also held various posts in the imperial guard and as a regional administrator. In 785, with the investiture of Prince Ate, the future Emperor Heizei, as Crown Prince, Mamichi was promoted to and appointed . In 790 Mamichi appealed to have his family's rank increased from "muraji" to "ason", and was granted the new family name of Sugano no Ason, based on his place of residence.