Leong was born and raised in Singapore, he is a son of Joseph, an owner of a newspaper stand, and Mary, an ex airline ticket sales executive.

[citation needed] Trained electric organ and classical piano from an early age, Leong developed a deep love with music.

In many interviews, he has mentioned the vocal stylings of Rob Thomas, Elvis Presley, Dave Gahan, David Bowie, Scott Weiland, Frank Sinatra, Dean Martin and Bono as strong influences.

"[citation needed] Towards the end of his military term, he formed the rock band, Reverie, taking the role of lead singer with other members of his unit.

[citation needed] Leong fronted rock band, Reverie, in the pub and club scene for four years as a means of income while attending university.

However, the performance that won the hearts of the Singaporean population was his take on Irish indie rock band Snow Patrol's hit song, "Chasing Cars", which placed Leong as the media's favourite for the title.

Leong finished the competition as 1st runner up in the finals held in the Singapore Indoor Stadium where he performed to a full crowd of more than 12,000 people.

In December 2006, Leong hosted a local holiday special series produced by Mediacorp named "Wish Upon A Star" alongside Hady Mirza and Gurmit Singh to fulfill contractual obligations.

In 2007, Leong was made an ambassador for the Motorola Singapore (RED) Campaign, an initiative spearheaded by Bono of U2 to alleviate the spread of HIV in Africa.

When interviewed if he was aware of the similarities between the two shows, Leong expressed ignorance during filming, but has since "immensely enjoyed" the original British sitcom after the fact.

He was featured as a celebrity guest contestant in the premiere episode of the Singaporean version of the popular television gameshow Don't Forget the Lyrics!.

In April 2010, it was announced that Leong would star in the original theatrical production, "Voyage De La Vie" along with a cast of international performers.