The first season of Two and a Half Men introduced some memorable characters who added to the show's enjoyable dynamic. Evelyn's relationship with Teddy, a con artist, and her daughter Courtney/Sylvia brought excitement to the storyline. Jake's friendship with Eldridge brought mischief and trouble. Kandi's relationship with Alan was short-lived but humorous. Dr. Linda Freeman provided sarcastic yet helpful therapy for Alan and Charlie.

Chelsea was a positive influence on Charlie's life. Jenny, Charlie's daughter, added a fresh new dynamic. Lyndsey and Alan's relationship was tumultuous. Herb became Judith's new partner. Finally, Walden brought a new dynamic to the show after Charlie's departure.