In 1973, his active military career came to an end and he became the Chairman of the State Audit Board (BPK), a position which he would hold until 1983.

[2] Umar's mother died when he was a child, and he and his siblings were cared for by his grandmother, Nyi Raja Juwita, who at that time lived in Cicalengka.

This was followed in October 1944 by PETA, an auxiliary force consisting of Indonesian recruits that was intended to assist the Japanese in fighting the Allies.

When Indonesia declared its Independence, Umar, like many other youths of similar age joined the TKR (People's Security Army), the forerunner to the TNI.

Umar served for a long time in Kodam VI/Siliwangi (Siliwangi Division) which was stationed in his native province of West Java.

After hearing about the kidnappings and seeing the unidentified troops occupying the Merdeka Square, Umar sent word to Kostrad Commander, Major General Suharto of the events that had just unfolded and requested his assistance.

Umar accepted Suharto's decision to assume command of the Army and supported him in his efforts to crack down on the attempted coup.

Towards midday, Umar received a summon from President Sukarno who was suspicious at Halim Perdanakusuma Airport, the place where the six Generals were taken.

When blame for the incident was beginning to be put on the Indonesian Communist Party (PKI), Umar approved of the formation of the Union of Action To Exterminate The 30 September Movement (KAP-GESTAPU),[4] leading to the mass killing of an estimated half a million people in 1965–1966.

In 1973, his active military career came to an end and he became the Chairman of the State Audit Board (BPK), a position which he would hold for 10 years.

This was considered to be a rather unexpected choice as Umar's stature in Indonesian politics paled in comparison to his two predecessors, Hamengkubuwono IX and Adam Malik.

Umar also conducted surprise inspections (sometimes incognito) of regional towns and villages to monitor how government policies were affecting the people.

His brother, Sadikin, was the father of Reini Wirahadikusumah, rector of Bandung Institute of Technology from 2020 until 2025 and was the first woman to hold the position.