Leonard is an accomplished singer, songwriter and guitarist who was barely into his teens when he landed his first gig still aged 14. He hasn't slowed down in the music industry ever since both domestically and internationally. Since his inception as a professional musician in 2000s, he has performed in a legion of concerts and events in Malaysia, Singapore, Australia, Dubai and China. His career has not ben without notable moments, one of those would be performing at the IMC Live “Rock on” music festival 2013 in Chengdu where he shared the stage with top Taiwanese and Hong Kong acts such as Beyond, Wu Bai and also Suede, from the UK to a festive audience of over 20,000.

In 2014, again in Chengdu China, he was the opening act for 'Soda Green', one of Taiwan's hottest band at the time or at the moment. He is not confined when it comes to the occasion as he has shown in the numerous times that his audience and venue has varied, from corporate dinners, charity events to local music scenes like Backyard, Waikiki, 1957, Bistro, Saltlick, Hangover, Souled Out and many more. He performed to a diverse audience from around the world in 2016 when he was engaged by the Raffles Hotel in Siem Reap, Cambodia for their 31st December countdown party. Leonard Theng's style has been entertaining crowds and getting them to groove to covers of hit songs from the 60s, 70s, 80s to the latest top 40s. His versatile vocal style from Jazz, pop and Rock doesn't fail to entertain either.