Jenkins was born Pretoria. At the age of 17 he wrote and had published A Century of History which received a special eulogy from General Jan Smuts at the centenary of Potchefstroom.
He subsequently won the Lord Kemsley Commonwealth Journalistic Scholarship, which took him to Fleet Street, where he spent World War II as a war correspondent. While working for the Sunday Times he became friends with author Ian Fleming, the creator of the British secret agent James Bond. Fleming later praised Jenkins' writing, saying "Geoffrey Jenkins has the supreme gift of originality.... A Twist of Sand is a literate, imaginative first novel in the tradition of high and original adventure'".
After the war Jenkins settled in Rhodesia, where he met his wife, author Eve Palmer (1916-1998). They married in 1950. He was the editor of the newspaper The Umtali Advertiser and eventually took up a position with The Star newspaper in Johannesburg.
It was while working for The Star that he wrote his first novel, A Twist of Sand (1959), which was subsequently translated into 23 languages and became a motion picture in 1968 starring Richard Johnson and Honor Blackman. He kept his newspaper job until he had published his third novel.
Connection with James Bond
After Ian Fleming's death it was reported that Glidrose Productions commissioned Jenkins to write a James Bond novel in 1966. Jenkins claimed that he and Fleming together developed a diamond-smuggling storyline in 1957. After a long period of negotiation, during which Anne Fleming (Ian's widow) raised several objections to the idea of a continuation series, Jenkins finished the manuscript for Glidrose entitled Per Fine Ounce, but it was rejected. The novel is believed lost, except for 18 pages now in the hands of Jenkins' son David. Two pages have been released to the public and were exclusively published by the James Bond website MI6.co.uk. Ian Fleming Publications (formerly Glidrose) allegedly returned their copies of the manuscript after rejecting it.
Jenkins' 1966 novel Hunter-Killer was a sequel to A Twist of Sand. It opens with the protagonist, Geoffrey Peace RN, faking his own death and funeral at sea, only to clamber aboard a submarine. It is strikingly similar to the pre-titles sequence of the James Bond film You Only Live Twice, which was released in 1967. No such scene took place in Ian Fleming's novel.
Three of his novels have been filmed. A Twist of Sand (1968) co-starred Honor Blackman. The River of Diamonds (1990) had been set for production in the 1960's. Dirty Games (1989), based on In Harm's Way, co-starred Jan-Michael Vincent.