מלכישוע's father is שאול and his mother is אחינועם. His paternal grandfather is קיש; his maternal grandfather is אחימעץ. He is the fifth of six children. He has three brothers and two sisters, named איש-בושת, יונתן, ישוי, מיכל and מרב. He has three half-brothers named ארמוני, מפיבשת and Abinadab ben.