Born in Overland Park, Kansas, Sarah moved to Mission Viejo, California, when she was 10 years old. In 1994, she secured her first role, as a series regular on Saved by the Bell: The New Class (1993). She then gained attention for her recurring role as "Madison Kellner" on the critically-acclaimed Warner Bros. series, Everwood (2002). She went on to star in Dr. Vegas (2004), for CBS from 2004-2006. Followed by ABC's What About Brian (2006), from 2006-2007. Sarah is perhaps best known for her lovable portrayal of "Ellie Bartowski" on NBC's long-running series, Chuck (2007). In 2014, Lancaster can be seen, alongside Robert Downey Jr., in The Judge (2014), for Warner Bros. Lancaster resides in Los Angeles with her husband, attorney Matt Jacobs, and their son, Oliver Jacobs.