He is the first son and second child of the current Pemangku Sultan (Regent) and Tunku Mahkota (Crown Prince) of Johor, Tunku Ismail ibni Sultan Ibrahim and his consort, Che’ Puan Mahkota Khaleeda Johor.
As his father is the heir apparent, upon his birth, Tunku Iskandar becomes second in line of succession to the throne of Johor.
He is the second child of Tunku Ismail ibni Sultan Ibrahim and his wife, Che’ Puan Mahkota Khaleeda.
In contrast to the Raja Muda of the states of Kedah, Perak, Perlis & Selangor, who are the heir apparents to their respective monarchies, the title of Raja Muda of Johor is bestowed upon to the eldest son of the heir apparent of the Sultan of Johor.
This tradition started when Almarhum Sultan Iskandar proclaimed his grandson, Tunku Ismail, as the Raja Muda of Johor in 2005.