Syed Waliullah was born on August 15, 1922 at Sholashahar in Chittagong. His father, Syed Ahmadullah, was a government officer whose postings took him to different mofussil towns in Bengal. The young Waliullah accompanied his father on his different postings, to Mymensingh, Feni, Chittagong, Krishnanagar, Kurigram. This peripatetic experience helped him to witness closely rural life in Bengal. It not only provided the backdrop of his writings, but also inspired some of his characters.
According to Khadija Zaman, his stepmother's sister, who was close to him in age, Lalsalu was inspired by a shrine covered with red cloth that he would often pass when he lived with his father in Mymensingh. After completing his BA from Anandamohan College in Mymensingh in 1943, Waliullah enrolled at Calcutta University to do Master's in Economics. However, he was unable to complete his MA and joined the Statesman, where he worked till 1947.