In full, Sultan Abu Bakar Riayatuddin Al-Muadzam Shah ibni Almarhum Sultan Abdullah Al-Mutassim Billah Shah, he was the fourth sultan of modern Pahang in Malaysia.

Born May 29, 1904 at Istana Hinggap, Pekan Lama, he was the second son of Sultan Abdullah Al-Mutassim Billah Shah by his wife, Che Kalsom binti Tun Abdullah.

Succeeding his father in 1932, he quickly became known as a friendly and approachable ruler by his subjects. During the Japanese Occupation of Malaya, he discreetly encouraged resistance movements such as the Askar Wataniah, Force 136 and the MPAJA.

However, due to his penchant for marrying commoners, including several popular actresses and singers, he was less popular with other Malay rulers and they declined five times to choose him as Yang di-Pertuan Agong of Malaysia.

He died on May 7, 1974 and was succeded by his son Sultan Ahmad Shah.