Raja Musa ibni Almarhum Sultan Abdul Aziz was born on 16 June 1919 at Teluk Anson. He was educated at the Malay School, Teluk Anson (1926 to 1929) and at the Anglo Chinese School, Teluk Anson (1929 to 1936). He then went to Clifford School in Kuala Kangsar from 1937 to 1939.
Raja Musa was appointed Raja Kechil Bongsu on 15 October 1938 and promoted Raja Kechil Muda on 1 January 1940. In the same year, he was sent to Taiping by his father, Almarhum Sultan Abdul Aziz, to be instructed in administration work at the State Secretariat. In 1941, Raja Kechil Muda Musa was attached to the Land Office as Assistant Collector of Land Revenue.
In 1945, Raja Musa was appointed Raja Kechil Sulong. For a little while, he was aide-de-camp to his father, Almarhum Sultan abdul Aziz in 1948. In 1950, he was appointed Orang Besar Jajahan Parit until 1952, before being transferred to Teluk Anson as Assistant District Officer for Lower Perak.
In 1953, Raja Musa was appointed Raja Kechil Besar. On 1 January 1956, he was appointed Secretary of the Dewan Negara Perak. He also held several positions which included president for the Council for Religious Affairs & Malay Customs, Perak Sports Club, and Perak Councils of Justices of the Peace.
On 1 August 1962, he was appointed Raja Di-Hilir and, a year later, appointed heir apparent, with the title of Tuanku Raja Muda Wakil us-Sultan Wazir ul-Azam on 1 February 1963, after the demise of Almarhum Sultan Yusuf Izzudin.
Almarhum Raja Muda Musa died on 12 May 1983 in London. He had issue – eleven sons and ten daughters. Almarhum is the father of the present DYAM Raja Di-Hilir, Raja Jaafar ibni Raja Muda Musa, and YM Raja Kobat Sallehuddin, one of the consultant editors of SembangKuala .