Complex sentence: Whilst Leigh is best known for playing online poker at PokerStars under the "Jennicide" alias, she was also involved in the series, where she won two preliminary heats, and went on to finish 5th in the Grand Final.
Split into simpler sentences: Whilst Leigh is best known for playing online poker at PokerStars under the screen name "Jennicide," she was also involved in the series. She won two preliminary heats and went on to finish 5th in the Grand Final.