Lil' Wally, also known as "Mr. Happiness," was a pivotal figure in the polka genre of music. Born Walter E. Jagiello in 1930, he was known for his energetic performances and unique Chicago-style polka, a slower-paced, more danceable variation of the traditional Polish style. He popularized this style through his influential works, including the international hit "I Wish I Was Single Again". His significance lies in his innovative approach to polka music, blending American jazz influences with traditional Polish rhythms, thereby reshaping the genre for future generations.