Frederich August is the sixth child and fourth son of Nikolaus, Hereditary Grand Duke of Oldenburg and his first wife Princess Helena of Waldeck and Pyrmont. His paternal grandparents are Frederick Augustus II, Grand Duke of Oldenburg and Duchess Elisabeth Alexandrine of Mecklenburg-Schwerin. His maternal grandparents are Friedrich, Prince of Waldeck and Pyrmont and Princess Bathildis of Schaumburg-Lippe.
