Maulana Mazharul Haq was born on 22 December 1866 in Bahpura, Patna, Bihar.
He received his early education at Patna College and Canning College, Lucknow and went to England in 1888 to study legal. There he was introduced to Mahatma Gandhi, which lasted for the rest of his life.He built a house in Faridpur Siwan Bihar and named it Ashiana. In the 18th century, Ashiana was a center for freedom fighters and was visited by many nationalists including Dr. Rajendra Prasad and Mahatma Gandhi.In 1891, he returned to India as a barrister and joined the judicial services. In 1896, he began practicing as a lawyer. In 1906, he left Chapra and started practicing in Patna and in the same year he was elected the Vice President of Bihar Congress Committee.
Between 1910-11 he was elected as a member of the Imperial Legislative Council of India (British Parliament). In 1911, a third "Bihar State Conference" was held under the chairmanship of Maulana in the conference to demand a separate Bihar state.
During 1919, he took an active part in the Khilafat Movement and in 1920 he joined the Non-Cooperation Movement on the call of Gandhiji. In 1921, Gandhiji was impressed and established "Sadkat Ashram" (abode of truth) in Patna. From the same ashram, Maulana started a weekly magazine called "Motherbhoomi". He was a strong advocate of Hindu-Muslim unity. His statement was "Whether we are Hindus or Muslims, we are on the same boat. If we win, we will sink, we will sink together".He announced his retirement from active politics in 1926, but leaders like Mahatma Gandhi, Maulana Azad and Nehru never left his side. He died on 2 January 1930. A residential colony in Siwan is named after him (Maulana Mazharul Haq Colony or better known MM Colony).A postage stamp was issued in his honor by the Indian Postal Service in 1981 and the Maulana Mazharul Haq Arabic Persian University was established in his memory in 1998 in Patna.