He was the son of Don Gabriel Fernández Manrique, 1st Count de Osorno and of Aldonza de Vivero.
In 1482, the Count married Teresa de Toledo, daughter of García Álvarez de Toledo, 1st Duke of Alba, with whom he had seven children. He married for a second time with María de Cabrera y Bobadilla, daughter of Andrés de Cabrera, 1st Marquis of Moya, with whom he had one more child.
By Teresa de Toledo:
By María de Cabrera: