Chowdhury joined the 6th Officers Training School Course of
Officers Training School, Kohat, in January 1958. He was commissioned in the
Pakistan Army Army Service Corps on 13 September 1958. He was promoted to
Major in April 1968. Later the 4th wing of EPR, led by Major Chowdhury and reinforced with police and Ansar personnel and local youth, attacked the 27 Baluch of the Pakistan Army stationed at Kushtia and eliminated almost 2 companies. In the first sector commander's conference in July, Chowdhury was appointed the commander of the western sector, which comprised
Kushtia,
Jessore, and areas of
Faridpur, including Doulatpur-Satkhira Road encompassed within
Khulna. It was past noon on 26 March when Chowdhury reached his wing headquarters at Chuadanga. There, his NCOs briefed him on the overall situation, including the formal organisation of local resistance in the wake of the crackdown at Dhaka. In the meantime, local Awami League leader Dr Ashab Ul Haq, who had earlier declared war against the occupying Pakistani armed forces the same morning at a public meeting, had contacted him over the telephone and invited him to an emergency meeting with the public leaders and representatives of the local administration. At the meeting, Chowdhury was asked to take charge of the armed resistance force, which he accepted at once. After a long discussion, the first-ever war command of Bangladesh, named South Western Command, was formed on 26 March 1971 in Chuadanga. While Chowdhury was given the position of the commander, Ashab Ul Haq, MPA became the chief advisor and Barrister Abu Ahmed Afzalur Rashid alias
Badal Rashid, MNA, and Advocate Yunus Ali, MPA, were made deputy chief advisors. The whole of western region of the Padma was taken under the command comprising that of Kushtia, Faridpur, Jessore, and Khulna districts. All the armed personnel from defence, EPR, police, Ansar, Mujahid and armed student wing of the area were vested under the command. The newly built District Council
Dak Bungalow was made the command headquarters. The next day, on 27 March at about noon the Pakistani flag, last flying one at the EPR Wing headquarters was ceremoniously lowered and the tri-colour Bangladesh flag was hoisted at the flag post by Chowdhury. Captain
A. R. Azam Chowdhury, his deputy, was there who afterwards played valiant role under the Command. Chowdhury held the position until the division of Bangladesh war commands into 11 sectors by the provisional government on 11 July 1971. The South Western Command was then renamed Sector-8 with some revision of the command area, and Chowdhury continued to hold the position of the sector commander until Major M Abul Manjur took over in September 1971.
Post war After the independence of Bangladesh, he was promoted to the rank of
lieutenant colonel and was appointed as the director of
Army Service Crops. On 7 November 1975, during the
1975 coup, Chowdhury's wife, Nazia Osman, was killed in his Gulshan residence. ==Later career==