Júlia Sebestyén was born on 14 May 1981 in Miskolc, Hungary. Her full name in Hungarian is Gór-Sebestyén Júlia.

Sebestyén began competing on the senior international level in 1995. She made her senior ISU Championship debut at the 1995 European Championships, where she placed 15th. She competed at the 1998 Winter Olympics and placed 15th. In the 1998–1999 post-Olympic season, Sebestyen competed on both the Junior Grand Prix and at senior ISU championships. She made her senior Grand Prix debut in the 1999–2000 season. During summers, she trained in Russia, Slovakia, Sweden, England and the United States due to lack of ice time in Hungary. In 2000, the Budapest ice rink burned down, forcing her to train at an outdoor rink in a city park.

Sebestyén competed at the 2002 Winter Olympics and placed 8th; she was also 8th at that season’s Worlds. The next season, she earned her first European Championships medal, a bronze. In 2004, she won the 2004 European Figure Skating Championships, becoming the first Hungarian woman to win that competition. She later finished 6th at the 2004 Worlds, which would prove to be her best result in that event.