[1] Fazlul Karim was born on 14 September 1905 to a Bengali family of Muslim Shiqdars in the village of Harbang in Chakaria thana, Cox's Bazar subdivision, Chittagong District, Eastern Bengal and Assam.

He was the eldest among the seven daughters and three sons of village leader Golam Quader Shikdar and housewife Feroza Begum.

He found his practice as a junior lawyer so lucrative that he refused to become a Munsif when he was offered a post by the Lieutenant Governor.

After completion of his B.A exams he joined the Writers' Building (from 1923 to 1926) as the infamous Police Commissioner Sir Charles Augustus Tegart's Bengali translator; as he was fluent in both Urdu and Bengali, he had to translate news from vernacular newspapers for Sir Tegart and Colonel Simpson's perusal.

At the age of thirty, Fazlul married Nazmunnisa Chowdhurani, elder daughter of Zamindar Akbar Ahmed Chowdhury and granddaughter of Kiwk Zamindar Fazal Karim Chowdhury of Manikpur, Chakaria, Cox's Bazar in 1935.

On 24 May 1986, Captain Advocate Fazlul Karim died at the age of 81 years in his Jamal Khan Road residence at Chittagong.