Sestak began playing piano, at the age of eight and a half, when he was sent by his parents to a piano teacher. In 2012 he told Birgitta Larsson of "Jefferson Blues Magazine":
"My father tried to teach me a little piano playing when I was 8, but I hated it. When I was nine and a half he sent me to a piano teacher. I didn’t like classical music at all. At eleven and a half, after two years of lessons, I was supposed to play a Beethoven sonata. It was after this point that playing the piano began to really give me pleasure. Today, however, my relating to classical music is diminishing again; to be honest, it isn’t easy to run on two tracks and my heart beats much louder for the blues."
After two years of classical piano lessons Sestak discovered jazz and blues music, in particular boogie-woogie, on the internet mainly through YouTube. Immediately captivated by this musical style, he began to teach himself blues piano while still taking classical lessons. In December 2006, he shared his first videos on YouTube which brought him public fame. In 2007, at the age of 12, Sestak visited the famous International Boogie Woogie Festival at Lugano, Switzerland, where he knew Axel Zwingenberger would perform.
By March 2014 his earliest videos had received as many as 1.8 million hits. After appearances in his home town of Karlsruhe, Sestak's fame continued to grow through videos. As he grew older, he began performing regularly in concerts and festivals in Germany, Austria, Switzerland, France, Sweden, Italy, Belgium, the Netherlands, USA and other countries, alongside Vince Weber, Ben Waters, Silvan Zingg, Pete York, Bob Seeley and Frank Muschalle.