Hailing from a clan of musicians, Jhonie has been playing since he was still a student at the University of Santo Tomas Conservatory of Music, alongside his father Joselito San Juan, who was a well-known violinist during his time, and his mother Ofelia, who was a flutist.

At a young age of 18, he was already playing at hotel lobbies and was teaching violin to beginner students of all ages. He was already actively performing in the events industry particularly at weddings and debuts.

In January 2009, Jhonie took a step further by performing on cruise ships with two others forming the trio. Their group earned quite a lot of good reviews from guests who had seen them perform.

Even while abroad, Jhonie's students would still keep in touch with him asking when he will be back because they wanted to continue their violin lessons with him. This only proves how effective his method of teaching is.

With the events industry greatly affected by the pandemic brought about by Covid-19, Jhonie does delivery services and do haircuts most of the time. He is also into web development as of the moment and is currently working on creating a website that would cater to delivery services. With his busy schedule, he still manages to teach violin every now and then, may it be online or in person.