Makibi's father was SHIMOTSUMICHI no Kunikatsu, Ueji no shojo (Jr. Lieutenant of the Right Guards), in Shimotsumichi District, Bicchu Province (later Mabi Town, Kibi County, Okayama Prefecture, and present-day Mabi Town, Kurashiki City), and his mother was from the local ruling family, the Yagi clan, of Yamato Province (later Nara Prefecture).
備中国下道郡（後の岡山県吉備郡真備町、現在の倉敷市真備町）出身の父は右衛士少尉下道圀勝（しもつみちのくにかつ）、母は楊貴氏（八木）氏（大和国（後の奈良県）の豪族）。