George Finch was born in New South Wales, Australia, but was educated in Paris and Zürich. He was a research chemist when he moved to Britain in 1912 and later served during the First World War with the Royal Army Ordnance Depot and the Royal Field Artillery. In 1915, at Portsmouth, Hampshire, George married Alicia Fisher, the daughter of a Kent barrister. However, George Finch was not Peter Finch's biological father. He learned only in his mid-40s that his biological father was Wentworth Edward Dallas "Jock" Campbell, an Indian Army officer, whose adultery with Finch's mother was the cause of George and Alicia's divorce, when Peter was two years old. Alicia Finch married Jock Campbell in 1922.
In 1934–35 he appeared in a number of productions for Doris Fitton at the Savoy Theatre, some with a young Sumner Locke Elliott. He also worked as a sideshow spruiker at the Sydney Royal Easter Show, in vaudeville with Joe Cody and as a foil to American comedian Bert le Blanc. At age 19 Finch toured Australia with George Sorlie's travelling troupe.
However, he was then cast as an Australian soldier in A Town Like Alice (1956), which became the third most popular film at the British box office in 1956 and won Finch a BAFTA for Best Actor. He followed it with The Battle of the River Plate (1956), playing Captain Hans Langsdorff. This was also successful financially and British exhibitors voted Finch the seventh most popular British star at the box office for 1956.
Finch returned to Australia to make The Shiralee (1957), one of his favourite parts, and the tenth most popular movie at the British box office that year. He followed it with another Australian story, the bushranger tale Robbery Under Arms (1957), which did less well. However exhibitors still voted Finch the third most popular British star of 1957, and the fifth most popular overall, regardless of nationality.
The number of Race to Dubai points available in the last three events of the season was increased, and the field size reduced. The aim was to make more players still have a chance of winning the Race to Dubai entering the final events. In addition, although the prize money was not increased, the bonus pool of US$5m would now be split among the top five players rather than the top ten. The money saved from restricting field sizes was used solely to increase the first prizes, which means that the tournaments would not have the standard prize fund distribution, and the DP World Tour Championship, Dubai would have the largest tournament first prize in golf of US$3m.
In 1953 he appeared in his first Hollywood movie, Elephant Walk (1954), shot in Ceylon and Los Angeles. The circumstances of production were turbulent; filming started with Vivien Leigh in the lead but she had a nervous breakdown during production and had to be replaced by Elizabeth Taylor. The experience helped sour Finch on a Hollywood career and he would only work occasionally there for the rest of his career.
Finch was married three times. In 1943, he married Romanian-born French ballerina Tamara Tchinarova; they worked together on a number of films. They had a daughter, Anita, born in 1950. They divorced in 1959, after she discovered his affair with actress Vivien Leigh in California. He then married South African-born actress Yolande Turner (née Yolande Eileen Turnbull); they had two children together, Samantha and Charles Peter. During their marriage, Finch had an affair with the singer Shirley Bassey. Bassey had a daughter, also named Samantha, born in 1963; Bassey's husband at the time, the openly gay film producer Kenneth Hume, believed that Finch was her biological father. Finch and Turner divorced in 1965. In 1972 Finch married Mavis "Eletha" Barrett, who was known as Eletha Finch. They had a daughter together, Diana.