At the start of Bangladesh Liberation War with Operation Searchlight, Amin immediately resigned from the Pakistan Navy, left PNS "Comilla" at Chittagong, and returned to his village. He organized local youths and soldiers for the war. In May, he along with 500 others joined at Sector-3 under Major K M Shafiullah. Later he enrolled at "Palash", a warship of Bangladesh Navy and at the same time worked as the squadron leader for both "Padma" and "Palash".