Family heritage is American, Vietnamese and Polish. Mother was born in Vietnam and came to the U.S. at age five. Father is half American and Vietnamese, but born in Poland. Last name 'Kwiatkowski' is Polish. Started playing tennis at age 5 because his grandma played a lot at their local tennis club in North Carolina. They would hit after she finished her matches. Began traveling to youth tournaments at age eight with his father: "My dad didn't know too much about the game, but we just strived to get better in competition. And because of that I've always been a fighter. I haven't had the biggest weapons, but I played a ton of matches in my life and worked hard for it."
