He obtained his MBChB from the University of Liverpool and later the FRCSEd (Otolaryngology) from the Royal College of Surgeons of Edinburgh.

[4] Zulkarnain was a Head and Neck Surgeon and otolaryngologist, who in 2001 was involved in the first Cochlear Implant Surgery on a child in Borneo at, Raja Isteri Pengiran Anak Saleha (RIPAS) Hospital.

[5] During the 2015 Bruneian cabinet reshuffle on 22 October,[6] Zulkarnain was sworn in as the Minister of Health.

[7] For the 2017–18 fiscal year, Zulkarnain's Ministry has been given a budget allocation of B$323.88 million, including B$7,766,900 for development expenses.

[9] His tenure concluded after two years, when Hassanal Bolkiah declared his approval for the nomination of Isham Jaafar on 1 December 2017.