Since both Ustad Ghulam Mustafa Khan's parents wanted him to be a singer, his training in music started very young at a time when he could remember the tune but could not understand the words.

He started with Mrinal Sen’s ‘Bhuvan Shome’ and sang ‘Sajanaa kahe nahi aaye...’ for ‘Badnaam Basti’ under the same music director, Vijay Raghav Rao.

He played the role of Baiju Bawra in a German Documentary "Rain Maker" shot in Jaipur, besides being playback singer in the same film.

From the late 50s, he has been a guru[4] to Lata Mangeshkar,[5] Asha Bhosle, Manna Dey, Kamal Barot, Waheeda Rehman, Ranu Mukherjee, Amit Kumar, Laxmi Nayampalli, Geeta Dutt, A. R. Rahman,[6][7] Hariharan,[8][9] Shaan and Sonu Nigam,[10][11][12] Sagarika, Alisha Chinoy, Shilpa Rao,[13][14] and Kalpana Patowary was one of his students.

Murtaza and Qadir have sung in films like Fiza,Meenaxi: A Tale of Three Cities, Saathiya, Guru, Mangal Pandey.

In Coke Studio, composer A. R. Rahman shared the stage with his 82-year-old guru, also featuring his four sons- Murtuza, Qadir, Rabbani and Hasan and his 12-year-old grandson, Faiz.

[17][18] Moreover his son Ghulam Murtuza Mustafa trained the singers and celebrities like Lucky Ali, Khatija Rahman, Raheema Rahman, A.R.Ameen (Children Of Music Composer A.R.Rahman) , Tabu, Huma Qureshi, Manmeet Singh, Khushboo Grewal, Neeti Mohan, Mohammed Irfan, Anushka Manchanda, Priyani Vani, Aishwarya Shankar, Aditi Shankar, Anjana Sukhani, Shazahn Padamsee, Shashwat Singh, Ashima Mahajan, Shefali Alvare, Garima Jain whereas Qadir Mustafa trained celebrities Elli Avram, VJ Andy, Terence Lewis, Armaan Mallik, Shraddha Kapoor, Rasha Thadani, Manav Gohil, Narayani Shastri, Simple Kaul, Tanzeel Khan, Band of boys, Sudhanshu Pandey, Turab Jaffery.