In Morrison's first appearance as a barrister, she was to act for a plaintiff widow claiming under the ''Testator's Family Maintenance and Guardianship of Infants Act''. She successfully established herself at the Bar and was on occasions briefed by fellow pioneering female lawyers, Christian Jollie Smith and
Marie Byles (also a school friend from her P.L.C days), both of whom had been admitted as solicitors in 1924. With her solid legal knowledge, Morrison was welcomed as a member of the National Council of Women of New South Wales, and was convener of their laws committee. In November 1926, she presented a paper on divorce in Australia when the National Council of Women was advocating uniform Federal marriage and divorce laws. She divorced her husband in 1928. Returning to London in 1930, Morrison was called to the Bar of the
Middle Temple in May. Back in Sydney, she remarried, this time to architect
Carlyle Greenwell on 16 March 1937, at St Stephen's Presbyterian Church. She was no longer listed as a practising barrister after this marriage. In 1940 she became the first president of the Law School Comforts Fund, becoming a life vice-president in 1942. She was also involved with what became the Business and Professional Women's Club of Sydney. Although Sibyl Morrison had been in competition with male colleagues throughout her career, it is said that she never lost her femininity, with a magazine noting that she was "an exceedingly smart up-to-date frocker". ==Death==