While serving as a member, he sought to secede from India and regain the Burmese monastery in Bodh Gaya through the hands of the Hindu monk Mahan.

Thein Maung served as Minister of Commerce of the Coalition Government (1937–1939) led by Dr. Ba Maw, which is part of the 91 departments of administration.

[6] Colonel Suzuki Keiji arrived in Burma in May 1940 and met secretly with Maung, Hmaing, Mya, and Lwin in September.

Japan-Burma Friendship Society Dr. Thein Maung[7] arranged for communication between Thakin Aung San and Colonel Suzuki Keiji.

After the end of the Second World War and the surrender of the Japanese army, Allied forces arrested and imprisoned Maung at the Burmese Embassy in Sugamo Prison, Tokyo.