Sadanobu was also known as a writer. He wrote using the pen name "Rakuō" (楽翁). Some of his notable texts include "Uge no Hitokoto", "Tōzen Manpitsu", "Kanko-dōri", "Kagetsutei Nikki", "Seigo", and "Ōmu no Kotoba", among others. After his death, it was learned that he had written a satirical text parodying daimyo life. It was named "Daimyō Katagi".