On daytime, Keller played the role of Amanda Kirkland on Ryan's Hope (1982–83) and the role of Sally Frame on Another World(1983–85). Moving to primetime, she played the part of Laura Kelly on two different Fox series, Duet and its spinoff Open House. She also appeared for one season (1990–91) on ABC's Life Goes On. Other series she has starred in include Baby Talk, Camp Wilder and Joe's Life. She has also appeared in the films Those She Left Behind (1989) and Picture Perfect (1995).
Keller has made guest appearances on numerous television series, including NYPD Blue, Nip/Tuck, Commander in Chief, JAG, NCIS, Criminal Minds, 24, Mad Men, Supernatural, Castle, Pretty Little Liars, Hart of Dixie, NCIS: Los Angeles, and Scandal. Keller also starred as Johnny Kapahala's mother in the Disney Channel original movie Johnny Tsunami. She played the mother in Beginners (2010).
In 2013 Keller was cast in ABC Family drama series Chasing Life, set to air in early 2014.