Royalty was born in Los Angeles, California, and began modeling at the age of 14. She appeared in numerous print and television advertisements before landing her breakthrough role as Heather Chandler in Clueless. The film was a critical and commercial success, and Royalty's performance was widely praised. She went on to star in several other films, including Scream (1996), I Know What You Did Last Summer (1997), and Urban Legend (1998).
In 1990, Royalty joined the cast of Beverly Hills, 90210. She played the role of Kelly Taylor, a popular and outgoing teenager who was often at the center of the drama. Royalty remained with the show for six seasons, and her performance earned her numerous awards and nominations.
After leaving Beverly Hills, 90210, Royalty continued to act in television and film. She has also appeared in several stage productions, including The Graduate and Chicago. In 2019, she reprised her role as Kelly Taylor in the new Beverly Hills, 90210 reboot.
In addition to her acting career, Royalty is also a successful entrepreneur. She is the founder of the fashion line The Rebecca Royalty Collection, and she has also released a beauty line and fragrance. Royalty is an advocate for several charitable organizations, including The Rape, Abuse & Incest National Network (RAINN) and Children's Hospital Los Angeles.
Royalty is married to actor Matthew Lillard, and they have two children.