Zaheer was born in Lucknow in 1905 and was the fourth son of Syed Wazir Hasan, a judge at the High Court of Judicature at Allahabad.
He attended the second Congress of the League against Imperialism held in Frankfurt, where he met influential leaders like Viren Chattopadhyay, Saumyendranath Tagore, N. M. Jaisoorya and Raja Mahendra Pratap.
[2][5] In 1935, he and novelist Mulk Raj Anand went to Paris to attend the International Congress for Defense of Culture organised by André Gide.
After returning to India, he organised the first conference of the Progressive Writers’ Association in Lucknow on April 9, 1936, and started working as its general secretary.
[6] He became Uttar Pradesh state secretary of the Communist Party of India (CPI) as well as a member of the working committee of the Congress in 1936.
"[10] This gave rise to the All-India Progressive Writers' Movement & Association of which both Sajjad Zaheer and Ahmed Ali were co-founders.
He also wrote Roshnai, a history-cum-memoir of the early days of the progressive movement (1956), Zikr-e-Hafiz, a critical look at the works of the legendary Persian poet Hafiz (1956), and a collection of poems in vers libre called Pighla Neelam (1964).
[6] In addition, Zaheer also served as the editor of several papers and magazines throughout his career including Bharat, Chingari, Qaumi Jung, Naya Zamana, Awami Daur and Hayat.