After his enrollment to the school, Quamrul kept himself busy with not only arts but with other activities such as sports and the Bratachari movement in 1939[3] and he also joined ARP during the Second World War.

He developed connections with the Forward Block, Gononatya Andolon (People's Theatre) and even with several leaders of the Communist Party,[3] got involved with the task of teaching of children and teenagers and contributed to illustrations in publications.

On 23 March, he put up at least ten propaganda posters portraying a monstrous face of Yahya Khan which inspired the freedom Fighters.

During liberation war he served as the Director of the Art Division of the Information and Radio Department of the Bangladesh Government in exile.

Getting inspired from Zainul Abedin, Jamini Roy, Quamrul Hassan chose to give the folk art tradition a breath of life by incorporating modern ideas in it.

Hassan was a versatile artist working in practically all media-oil, gouache, watercolors, pastel, etching, woodcut, linocut, pen and pencil.

However, he mixes romanticism with realism; the strong curved lines and the contrasted use of color contribute to a sensuous appeal that blunts the edges of harsh reality.

His paintings of women can be divided into three phases: the 50s Love and Premarital stage, the end of 50s and the beginning of 70s the happy conjugal life, and the 70s and the 80s the time of marital separation.

And the third stage marks the time when he and his wife were separated due to some reasons and at this period instead of highlighting some emotions that are visible in his other paintings, he kept on drawing female nudes.

His series titled Image'74 shows his political view which portrays the tendency of sacrificing morals and ethics over some personal gains among politicians, bureaucrats and the businessmen of Bangladesh.