Susan Michaela Sullivan (born November 18, 1942) is an American actress with credits in daytime and primetime programs. Sullivan is best known for her roles as Lenore Curtin Delaney on the daytime soap opera Another World (1971–76), as Lois Adams on the ABC sitcom It's a Living (1980–81), as Maggie Gioberti Channing on the primetime soap opera Falcon Crest (1981–89), as Kitty Montgomery on the ABC sitcom Dharma & Greg (1997–2002), and as Martha Rodgers on Castle (2009–2016).
Sullivan was born in New York City, the daughter of Helen (née Rockett) and Brendan Sullivan, an advertising executive. She was raised in the Long Island village of Freeport, Nassau County, New York, where she graduated from Freeport High School in 1960. She earned a BA in drama from Hofstra University in 1964. She got her acting start in the 1960s playing opposite Dustin Hoffman in the Broadway play Jimmy Shine. She landed a contract with Universal Studios in 1969, guest-starring on several series. It was during this time that she played roles in daytime dramas.