When Emperor Gokomyo died, his adopted son and younger brother, Imperial Prince Satohito (the Emperor Reigen) had just been born, and the other brothers were all living the religious life, Emperor Gosai was enthroned on November 28, 1654 until Imperial Prince Satohito was old enough to succeed to the throne.
後光明天皇が崩御した時、同帝の養子になっていた実弟識仁親王（霊元天皇）はまだ生後間もなく他の兄弟は全て出家の身であったために、識仁親王が成長し即位するまでの繋ぎとして、1654年（承応3年）11月28日に即位。