Abang Hashim's career in the Judicial and Legal Service began on 1 August 1983 when he was appointed as a magistrate in Miri, Sarawak.

[1] Nevertheless, he was to return to the judicial service the following year having been made a Sessions Court judge at the national capital of Kuala Lumpur.

Upon leaving the AGC, Abang Hashim was then appointed as the chairman of the Department of Cooperative Development Malaysia Tribunal for a period of one year.

[1] On 14 October 2009, Abang Hashim was confirmed as a full High Court judge and continued to serve in Kuala Lumpur until the end of 2012.

[1][5][6] As senior most judge from East Malaysia in the Federal Court, Abang Hashim was appointed as David Wong Dak Wah's successor in an acting capacity as CJSS on 20 February 2020.