Susannah Winnifred Flood (born June 30, 1982) is an American actress known for her work in the theatre.
Flood is the daughter of Peter Gosnell Flood, an acting teacher and lifetime member of the Actors Studio. Prior to his marriage to her mother, Virginia, he was married to musical theatre actress Betty Buckley from 1972 until 1979. Flood spent her early years in New York City and Los Angeles.
She studied English at the University of California, Berkeley and went on to earn a Master of Fine Arts in Acting from Brown University, graduating in 2007.
Flood is known for her work Off-Broadway, originating roles in new plays. In 2023, she originated the role of Caitlin in The Comeuppance by Branden Jacobs-Jenkins. In 2024, she played the role of Mina in Abe Koogler's Staff Meal.
She made her Broadway debut in 2016, playing the role of Dunyasha in The Cherry Orchard. In 2022, she returned to Broadway in the new play Birthday Candles, playing multiple roles. In 2025, Flood played the lead role of Lizzie in Liberation by Bess Wohl directed by Anne Kauffman. Flood starred in the original Off-Broadway production from January 31, 2025, through March 30, 2025, continuing on to Broadway from October 8, 2025, until the play closed on February 1, 2026.
On television, she played Ann, the sister of Amy Schumer's character on Life & Beth and Kate Littlejohn in the television series For The People. On film, she played Dorothy in The Chronology of Water, directed by Kristen Stewart.
She is in a relationship with actor J.D Taylor, with whom she has one child.