Sybil Lines started her career as Marion Lines but now uses her middle name to avoid confusion with another actress.
Film and television credits include: the villainess Libby Webster on The Edge of Night, Madge on Murder She Wrote, Gloria on The Hogan Family and James Fox's wife in Mickey Blue Eyes. In 2008 Sybil devised and directed an audience-participation version of The Cherry Orchard by Anton Chekov and in 2013 she wrote Bastard Blood (two promenade plays that run concurrently and sometimes overlap) telling of the 'Wars of the Roses' through her own text and Shakespeare's. In 2015 she co-directed an Equity showcase of Alice! with the playwright, Patrick Cann, and other collaborations include Thistle & Rose with Linda Gates; After the Garden with Gerald Duval and co-writing Rough.In.Proof with Sea McHale which, in 2012, she also directed as an Equity showcase.