Jakab was the son of Dobó Ruszkai and NN Sebesi. The date and place of his birth have not been found.
His wife was Anna Ládi. They were married, but the date and place have not been found. Their five known children were Domokos (?-<1395), Balázs (?-<1432), István (?-?), László (?-?) and Anna (?-?).