Chikanaga served the 13th Shogun Yoshiteru ASHIKAGA, ruling over Kirinokawachi, Funai County, Tanba Province, living in Bankonji Castle along with his father Chikayo; however, in 1565, Yoshiteru was defeated by Hisahide MATSUNAGA and Chikanaga lost his territory.
13代将軍足利義輝に仕え、丹波国船井郡桐野河内を領して蟠根寺城に父の親世とともに拠ったが、永禄8年（1565年）義輝が松永久秀に討ち取られ、親長は所領を失い没落。