Judge Elizabeth Gaynor was born in 1955, the eldest of 12 children. Her father, Bernie Gaynor ran a well-known legal firm, Rennick and Gaynor, and was a formidable influence in the young Liz' decision to study law.

In 1972, Liz completed Year 12 at Loreto Mandeville Hall, excelling in debating and sport, and was accepted into the arts law course at Melbourne University, graduating in 1978.

Upon completion of her degree, Liz did articles at her father's firm, but decided on a change of career, going to work for the Australian Associated Press (AAP) as a journalist covering general, industrial, police, court and state rounds. She reported on (among other things) the Costigan Royal Commission and also did a stint in Canberra as a parliamentary reporter.

Returning to law in 1983, Liz spent twelve months with the Victoria Legal Aid Commission as a duty solicitor at Prahran Magistrates' Court and the Children's Courts in Melbourne, Dandenong, Springvale and Ringwood.

In June 1985, Liz signed the Victorian Bar Roll and commenced a criminal trial defence practice lasting seventeen years. She read with Ray Perry, and later was defence counsel in trials for murder, attempted murder, serious assaults, rape, incest, blackmail, kidnap, arson, drug importation, drug trafficking, burglary, theft, forge, utter, financial deception etc. During this period, she appeared regularly before the Psychologists Registration Board for practitioners. She was also assistant convenor for the Women Barristers Association.

During her career at the Bar, Liz had four readers: Trish Devlin, Greg Smith, Maureen Green, and Sharon Lacey.

In January 1990, Liz married fellow barrister John Smallwood whom she'd met at her Bar Readers' Course. The couple have two children. Liz and John's lives as barristers and parents were shown to considerable effect in a 1997 television documentary, For the Defence (produced by December Films).

Before being made Judge of Victoria's County Court in 2001, John likewise had an extensive criminal defence practice (consisting primarily of murders).