When did Renee Walker first appear in 24?

Renee Walker first appeared in 24 in the fifth season. She is a CTU agent and is portrayed by Annie Wersching. She is introduced as a junior agent who is assigned to help Jack Bauer when the fifth season begins. Renee and Jack quickly develop a strong bond and she becomes his partner, aiding him in his mission to capture terrorist mastermind Abu Fayed. Throughout the season, Renee helps Jack in stopping terrorist attacks, apprehending bad guys, and uncovering conspiracies. She is an invaluable asset to Jack and to CTU, and she ultimately helps Jack succeed in stopping the day's events. She and Jack have a romantic relationship which serves as a major subplot of the fifth season. Renee leaves the show at the end of the fifth season and returns again in the seventh season.