The Sultan of Johor died on 22 January 2010 at age 77 at the Puteri Specialist Hospital after being admitted earlier in the day following an illness.

He was buried in the Mahmoodiah Royal Mausoleum the next day at 2 pm. Before that, the public was allowed to pay their last respects to Sultan Iskandar from early morning.

Sultan Mahmud Iskandar Al-Haj ibni Ismail Al-Khalidi (8 April 1932 – 22 January 2010) was the eighth Yang di-Pertuan Agong (King) of Malaysia, from 26 April 1984 to 25 April 1989. He succeeded his father, Sultan Ismail, to become the 24th Sultan of Johor upon the former's death in 1981.

Sultan Iskandar (known as Tunku Mahmud Iskandar until 1981) was the third son of Sultan Ismail ibni Sultan Ibrahim by Sultanah Ungku Tun Aminah binti Ungku Paduka Bena Sri Maharaja Utama Ahmad, and was born on 8 April 1932 in Istana Semayam, Johor Bahru.   Tunku Mahmud received his education in Johor Bahru, Trinity Grammar School, Australia and  Upper Chine School  in the United Kingdom. Upon completing his studies, Tunku Mahmud returned to Malaysia in 1956 and briefly served as a cadet officer in the Johor Civil Service, taking charge of affairs in District Affairs, Land and Treasury departments until his appointment as the Tunku Mahkota of Johor in May 1959.
Under the elective monarchy system of Malaysia, Sultan Iskandar was elected to be the new Yang Di-Pertuan Agong on 9 February 1984 by the council of rulers.  He succeeded the Sultan of Pahang as the Yang-Di Pertuan Agong on 26 April.   Sultan Iskandar served in the capacity as the Yang-Di Pertuan Agong until 1989.

As a youth, Tunku Mahmud qualified as a pilot, having trained in handling light and medium aircraft and was known as an ace helicopter pilot. He was also adept in handling motorcycles, reportedly possessing the skills to strip a motorcycle down to its component parts and then reassembling it.

The Sultan is also well-known for his passion in many types of open-air sports, especially golf and polo.   An avid polo player, he led his Royal Johor polo team to many tournament victories in Malaysia and Singapore and around the region. 

He hosted many international polo teams and some of the best players in the world at the Royal Johor Polo Club in private matches and tournaments. 

The Sultan became a close friend of HRH Sultan Hassanal Bolkiah of Brunei, with whom he shared the passion of polo. 
Although the Sultan retired from tournament polo in the 70’s, he continued to play club polo at the superb facilities at his Royal Johor Polo Club, and at his palace, Istana Bukit Serene. 
His love for polo has been passed on to his sons, Sultan Ibrahim Sultan Ibrahim Ismail Ibni Almarhum Sultan Mahmud Iskandar Al-Haj, Tunku Abdul Majid Idris Ibni Sultan Mahmud Iskandar Al-Haj, and their children.