Umar received his MA in Philosophy from Dhaka University and his BA Honors degree in PPE (Philosophy, Politics and Economics) from Oxford University. Umar began his academic career as a teacher at Dhaka University on a temporary basis. In 1963, he joined Rajshahi University as the founder-chair of the Political Science department. He also founded the department of Sociology at the same university, but he resigned from his university positions during the hostile times of the then East Pakistan governor Abdul Monem Khan to become increasingly more active and engaged as a full-time leftist political activist and public intellectual to fight for the cause of oppressed peasants and workers in Bangladesh.
As a follower of Marxist-Leninist principles, Umar began writing anti-colonial articles from the 1970s. In the 1960s he wrote three groundbreaking books––Sampradayikata (Communalism, 1966), Sanskritir Sankat (The Crisis of Culture, 1967), and Sanskritik Sampradayikata (Cultural Communalism, 1969)––that theorize the dialectics of the political culture of ‘communalism’ and the question of Bengali nationalism, thus making significant intellectual contributions to the growth of Bengali nationalism itself. In 1969, Umar joined the East Pakistan Communist Party (Marxist-Leninist), and from February 1970 to March 1971, Umar edited the mouthpiece of the East Pakistan Communist Party––Saptahik Ganashakti—which published essays and articles about the problems and prospects of the communist movement in Pakistan. He was president of both Bangladesh Krishak Federation (Bangladesh Peasant Federation) and Bangladesh Lekhak Shibir–the country’s oldest organisation of progressive writers, intellectuals, and cultural activists.