Adored by millions on both sides of the border for his golden voice, the 84-year-old ghazal maestro, who died in a Karachi hospital today following multi-organ failure, was one of the last icons representing the shared cultural heritage of India and Pakistan.
His demise has brought the curtains down on an era of lyricism and poetry.
An inspiration to generations of singers in both the countries, Hassan's mesmerising voice and range made him 'Shahenshah-e-Ghazal' (The King of Ghazal singing).
Aaye kuchh abr kuchh sharaab aaye; Patta Patta, Boota Boota; Dil-E-Nadan Tujhe Hua Kya Hai and Dil Ki Baat Labon Par Laakar are among the his all-time hits.
Hassan was born into a family of traditional musicians at Luna village in India's Rajasthan state on July 18, 1927.
Belonging to the 16th generation of musicians from the Kalawant clan, Hassan received his musical grooming from his father Ustad Azeem Khan and uncle Ustad Ismail Khan who were both traditional 'dhrupad' singers.
He started performing at a young age and his first concert was on 'dhrupad' and 'kheyal' with his elder brother.
Hassan's family migrated to Pakistan at the time of Partition in 1947 when he was just 20.
The family was living in poverty but despite the hardships, Hassan's passion for music did not wither and he kept up the routine of 'riyaz' (practice) on a daily basis.
In an attempt to make both ends meet, Hassan started working in a bicycle shop. The singer got his first break on Radio Pakistan in 1957.
Hassan, who married twice, is survived by 14 children --
nine sons and five daughters. His wives predeceased him.
The maestro, who began his career primarily as a thumri singer, earned recognition within the musical fraternity at the time when Ustad Barkat Ali Khan, Begum Akhtar and Mukhtar Begum were considered the stalwarts of ghazal rendition.
It was his passion for Urdu poetry that made him take up ghazal singing on a part-time basis but he soon became its greatest star.
There was a time in Pakistan's film industry when a film was considered incomplete without Hassan's voice. He ruled the Pakistani film world along with Ahmed Rushdi in the 1960s-70s.
He was the recipient of numerous awards and recognitions: the Tamgha-i-Imtiaz granted to him by Gen Ayub Khan; the 'Pride of Performance' bestowed on him by Gen Ziaul Haq; and the Hilal-i-Imtiaz conferred by Gen Pervez Musharraf.
Besides the Nigar Film and Graduate Awards from Pakistan, he was presented the Saigal Award in Jalandhar, India, in 1979, while the Gorkha Dakshina Bahu Award was given to him in Nepal in 1983.
Hassan stopped singing in the late 80s due to ill health.
Despite his ailments, Hassan had a great desire to sing with Lata Mangeshkar. In 2010, Sarhadein, an album which had the first and last duet song Tera Milana by Mehdi Hassan and Lata Mangeshkar, was released.
Hassan recorded his part in Pakistan in 2009 and Lata later heard the track and recorded her part in India in 2010. The tracks were later mixed together for a duet.
Lata, who once called Hassan the 'voice of God', said "A singer like him is born once in a millennium. It is my bad luck that I could not sing with him when he was healthy. Now I can only regret. With his demise the music fraternity has lost a great and legendary singer."
Hassan, who last performed in India in 2000, wanted to visit his birth country again, a wish that remained unfulfilled.