Born to a Malaysian Punjabi father, Chainchal Singh and a Chinese–Japanese mother, Gurmit was brought up as a Sikh, but converted to Christianity in 1985. Gurmit Singh studied in Outram Secondary School during his secondary school years.
Making his debut in the variety show Live on 5 in 1994, he then became the host and lead actor of sitcom Gurmit's World. The second season of Gurmit's World, in which Gurmit portrayed his 'relatives' in a series of skits (unlike the first season where he played a wide assortment of mostly non-recurring characters), featured the first appearance of a character named Phua Chu Kang. The Singlish-based spin-off sitcom Phua Chu Kang Pte Ltd in 1996 made Gurmit a popular icon in the recent years, not only in Singapore, but also in neighbouring countries (especially culturally similar Malaysia). This factor led him to be the host of Singapore Idol. In the past few years,[when?] Gurmit has also won the Top 10 Most Popular Male Artistes at the Star Awards.
In November 2014, Gurmit announced the end of his full-time television career at MediaCorp after exactly 20 years. Gurmit shared that he planned to spend more time with his family and would take on artiste engagements on a more selective basis.