In East Pakistan Dey began his club football career in
East Pakistan with then renowned club Khulna Heroes of Khulna First Division League in 1961 after gaining success in playing for local Khulna-based sides. In the Khulna First Division League, his dazzling sportsmanship caught the attention of football fans, and he was picked up by
Dhaka First Division League club
Dhaka Mohammedan. Two legendary Dhaka Mohammedan players
Kabir Ahmed and
Amir Jang Ghaznavi played a crucial role in this transfer. in 1964. Dhaka Mohammedan and
Karachi Port Trust were joint-winners of the tournament. He also played for Khulna Town Club in 1963.
In India After his arrival in
Calcutta in 1965, Jyoti Prakash Mitra wrote in 1982 in
Khelar Kagaz about the journey of Dey from East Pakistan to
Pakistan national football team under the headline "Padma to Ganga". Dey later became an Indian citizen but got less opportunities and appeared in only a few matches from 1965 until 1967. Thus he moved to
Aryan Club, one of the oldest clubs founded in 1884. With Aryan, he appeared in 1967 Calcutta League and in a match, his goalkeeping helped the team winning 2–1 against Mohun Bagan. In Indian club football, he was in hard times until his signing with
Mohun Bagan in 1968. In 1969, Mohun Bagan clinched the Calcutta Football League title under the guidance of legendary coach
Amal Dutta. He also helped the "green and maroons" winning major titles including
Rovers Cup in 1968, 1970 and 1971, and
IFA Shield in 1969. His goalkeeping for Mohun Bagan at the final of 1969 IFA Shield, helped the team winning the trophy defeating his former club East Bengal 3–1 and it was club's eleventh Shield victory. Amal Dutta was influential nurturing talents including Balai Dey and others like
Monoranjan Bhattacharya,
Satyajit Chatterjee. He moved back to SC East Bengal in 1972 and played consecutively until 1974. During his spells with the "red and gold brigade", he won Calcutta Football League in 1972 and 1973, IFA Shield in 1972 and 1973, Rovers Cup in 1972 and 1973,
DCM Trophy in 1973 defeating North Korean side Dok Ro Gang, and
Bordoloi Trophy in 1973. Dey also appeared in the jersey of
State Bank of India. Between 1967 and 1970, he represented
Bengal in
Santosh Trophy and emerged champions in 1969. During the national camp in
Bombay, Dey had to rush to Nowgon,
Assam, in a few hours' notice after receiving an SOS from the Bengal team management and participated in the Santosh Trophy. In final, they defeated
Services by 6–1. ==International career==