Tudhaliya was likely born in his father's court in Hattusa, after his brother and crown prince Nerikkaili, but still while their father was governing on his brother Muwatalli II's behalf. He was a good friend of Muwatalli's son, Kurunta, and Hattusili ordered that they stay on good terms.
After Hattusili as King wrote up a treaty with "Ulmi-Tessup" which confirmed Kurunta's rule over Tarhuntassa, Hattusili elevated Tudhaliya over his older brother to be his crown prince. Tudhaliya as king drew up a bronze tablet treaty confirming the links between him and Kurunta. During his reign, 13 dams were built after a severe drought, one of which still survives to this day at Alacahöyük.
^King (lugal) of Tarhuntassa (Bryce 1997, p. 296); apparently later Great King of Hatti (Bryce 1997, p. 354).
^Nerikkaili married a daughter of Bentesina, king of Amurru (Bryce 1997, p. 294).
^Two daughters of Hattusili III were married to the pharaoh Ramesses II; one was given the Egyptian name Ma(hor)nefrure. Another, Gassuwaliya, married into the royal house of Amurru. Kilushepa was married to a king of Isuwa. A daughter married into the royal family of Babylon. A sister of Tudhaliya IV married Sausgamuwa, king of Amurru after his father Bentesina. From Bryce (1997), pp. 294 and 312.