Nina Murdoch was the daughter of law clerk John Andrew Murdoch and his wife Rebecca (Murphy). She grew up in Woodburn, New South Wales, attending the school conducted by her mother until the age of eleven. Murdoch then moved to Sydney and became a student at the Sydney Girls' High School from 1904 to 1907. She contemplated going to university, but decided not to seek funds from her father's family to enable this course; instead she returned home and taught with her mother and, later, taught at the Sydney Boys' Preparatory School.
Murdoch began writing poetry while at high school and published prolifically in the Bulletin between 1913 and 1922. In 1913 she won the Bulletin prize for a sonnet about Canberra. She worked for the Sydney Sun and became one of the first women general reporters. In 1917 she married James Duncan McKay Brown, an ex-teacher and journalist who had lost an arm. The Browns moved to Melbourne, and worked on the Melbourne Sun News-Pictorial. Murdoch was the first woman in Melbourne to do general work on the staff of a newspaper.
In 1927 Murdoch travelled alone in England and Europe, developing a love of travel which led to her writing a number of travel books. In 1930 she and other married women were retrenched from the Herald because of the Depression. She gave travel talks on the wireless, and from the earliest days of the ABC in 1932, managed the Children's Corner on 3LO. She founded the children's radio programme 'The Argonauts Club', running it under the name of 'Pat'. In 1933 her husband moved to Adelaide to work for News Ltd, and Nina followed him the next year. During this period she travelled again and published two travel books, as well as doing war work and some broadcasting before returning to Melbourne in about 1942.
In her later years Murdoch spent much time looking after her blind mother, who lived to the age of 105, and her husband who was asthmatic and died in 1957. Murdoch herself died in 1976 after spending her last years in a nursing home at Camberwell.