Sybil Thorndike was the eldest daughter of a clergyman. Though she was born in Gainsborough she spent most of her childhood in Rochester. She intended to have a career as a concert pianist but ill health put a stop to that ambition. Instead she turned her attention to acting. Her three siblings also tried acting careers though the most successful of them, Russell would become more famous as the author of Dr Syn.
Sybil was taken on by Ben Greet and toured America with the company for over a year. Her second US tour was cut short by vocal problems but after a period of enforced silence she resumed her career. She met her future husband Lewis Casson while understudying in Miss Horniman's company. They married in 1908 and would have four children.
With the outbreak of World War I, Lewis joined the army. Sybil joined the Old Vic and spent much of the war there playing virtually every female role in Shakespeare, plus a few of the male. After the war, she scored a big West End hit in The Trojan Women. Lewis then joined her for several seasons of Grand Guignol.
The highlight of her career came in 1924 when she created the role of Saint Joan which Shaw wrote with her in mind. She became indelibly linked with the role and played it off and on for the next ten years. Her next biggest success was in Emlyn Williams' The Corn is Green as the schoolteacher Miss Moffat.
During much of World War II, she and Lewis toured for CEMA. They took culture to the country including Macbeth to the miners of South Wales. After the war, they scored another hit with Priestley's The Linden Tree.
As the decades rolled on, she and Lewis continued to work heroically. He became president of Equity and only failing eyesight slowed him down. He died in 1969. She gave her final performance in the same year at the new theatre in Leatherhead named after her. Her final public appearance was in 1976 at the National Theatre's farewell performance at the Old Vic before moving to its South Bank home.
Sybil's film career was less distinguished than her stage work but she did manage to produce a few memorable performances.
| 1921 | Moth and Rust (short) |
| 1922 | Bleak House (short) |
| 1928 | Dawn |
| 1929 | To What Red Hell |
| 1931 | Hindle Wakes |
| 1932 | A Gentleman of Paris |
| 1936 | Tudor Rose |
| 1941 | Major Barbara |
| 1947 | Nicholas Nickleby |
| 1948 | Britannia Mews |
| 1950 | Stage Fright |
| 1951 | The Lady With the Lamp |
| 1951 | The Magic Box |
| 1953 | Melba |
| 1953 | Weak and the Wicked |
| 1957 | The Prince and the Showgirl |
| 1958 | Alive and Kicking |
| 1958 | Smiley Gets a Gun |
| 1959 | Shake Hands with the Devil |
| 1960 | Hand in Hand |
