Taught Bengali and linguistic in Dhaka University from 1957 – 1958 and 1961 till 2004 as Senior lecturer, Assistant Professor, Associate Professor and Professor. Head in Bangla, Dhaka University. Also held the position of Nazrul Professor, Dhaka University and Director General (2001-2002) of Bangla Academy. Ex-Vice Chancellor (2007-2011), ULAB, Professor Emeritus and Advisor (2011 – till now), Center for Bangla Studies, ULAB. National Professor (01st July 2018 till now).
More than 30 scholarly books on Life and works of Kazi Nazrul Islam, History of Language movement (1948-52), History of Liberation war of Bangladesh (1971), History of Dhaka University (2004), History of Shaheed Minar (1986), History of Dhaka City (1982), An Introduction to Colloquial Bengali (1970), Biography of the Martyr Intellectuals of 1971 Liberation War (1973), Joint Editor of the Standard Colloquial Bengali Grammar (2011) published by Bangla Academy, Dhaka. Edited 12 volumes of Nazrul’s works (2007-2010) published by Bangla Academy, Dhaka. Edited Abul Monsur Ahmed’s Rochonaboli published by Bangla Academy, Bangali Language and Literature of the millennium. A documentation of the Bengali Language and Literature of the last millennium. (1000 forma) by CBS(2016), ULAB.
Large numbers of research articles in various National and International Journals on the life and works of Kazi Nazrul Islam and linguistics with special reference to Bengali Language and Literature.
Research guide of 11 M.Phil and 6 PhD research scholars from Dhaka University.
- Fulbright Scholars, USA (1959-60)
- Linguistics Adviser, US Peace corps (1963)
- Summer School of Linguistics At Central Institute of Indian Languages, Mysore (1973)
- Summer School of Linguistics At University of Mishigan, An arbour, US (1974)
- Summer School of Linguistics At East-West Center, University of Hawaii, (1978).
- Actively participated in 1952 the language movement and also took part in liberation war of Bangladesh (1971).
- Nazrul Academy Award, Churulia, West Bengal (1987)
- Nazrul Institute Award, Dhaka (1987).
- Bangla Academy Award (1994)
- Ekushey Padak (2001)
- Shadhinota Purushkar (2012)
- Television Channel Eye Life Time Award (2010)
- Marchentail Bank Life Time Award (2011)
- Bangla Academy Shommanona (2017).