Being advised by Sir Ashutosh Mukherjee he joined the Calcutta High Court and started legal practice.
In 1913 Huq became the Secretary of the Bengal Provincial Muslim Leagueand continued in this post till 1916. Previously, he took an active part in forming the All India Muslim Leagueat Daccaon 30 Dec. 1906. Huq was the President of All India Muslim Leaguefrom 1916 to 1921. As a member of the Indian National Congress he was also actively connected with this organisation.Huq was one of those who were instrumental of formulating the Lucknow pact of 1916 between the Congress and the Muslim League. In 1917 Huq was a joint secretary of the Indian National Congress and in 1918-1919 he served this organisation as a General Secretary.In 1918 Huq Presided over the Delhi session of the of the All India Muslim League . In 1919 Fazlul was chosen as a member of the Punjab enquiry committeealong with Motilal Nehru, Chittaranjan Dasa nd other prominent leaders set up by the Indian National Congress to go into the Jalianwalah Bagh Massacre. Huq was the President of the Midnapore session of the Provincial Conference in 1920.