He had close relations with the Emperor Junna, who had a mother from Fujiwara Shikike and was the same age as Yoshino (Some say that he was a foster brother to the Emperor Junna.), and devoted his life to the Emperor.
式家出身の母を持つ淳和天皇とは同年齢で親しく（天皇の乳兄弟とする説もある）、その生涯を天皇の為に捧げる事になる。