In 1205, he had genpuku (celebrate one's coming of age) at residence of grandfather of the mother's side, FUJIWARA no Sanemune, and was adopted by his uncle Kintsune SAIONJI.
1205年（元久2年）、母方の祖父藤原実宗邸で元服を行い、伯父西園寺公経の猶子となる。