Clifford's father was a magician and as a child he enjoyed classic magicians at the Tivoli, such as comedy duo "Null & Void" and Chang's Chinese show A Night in Hades. Inspired, Clifford began learning tricks from Popular Mechanics.

Aged 18, Clifford was working for Qantas while establishing himself as a magician and ventriloquist when he met Dr Paul White, "the Jungle Doctor". The two collaborated frequently throughout the rest of their lives.

White assisted Clifford to get into radio. From 1948 to 1951, he did the breakfast show and an afternoon children's program on Inverell's radio 2NZ as Rex Clifford. He wrote and produced a weekly radio pantomime using his ventriloquist character "Dudley". This won him an Australian Broadcasting Tribunal award in 1948.

In 1951, White assisted Warne to get a position at the Scripture Union helping prepare for the introduction of television. In 1955/56, White sponsored Warne to study film and television in the United States. He spent time in Britain, Africa and Europe, and appeared the NBC network in New York, CBC Toronto and CBS Hollywood.

In 1957, six months after ATN7 began broadcasting, Warne began magic and ventriloquist performances twice weekly on the Captain Fortune Show. He also hosted the Ruff and Ready Cartoon Show Monday to Friday for a couple of years. He worked with the Seven Network for thirty-seven years, up to the 1990s.

Warne became the first director of the Church of England Television Society in 1957. For 15 years, he produced The Wotsaname Show featuring Martha Nixon and his puppets, broadcast on ATN 7 and regional stations. He also produced adult religious television, such as the panel Time to Talk.

As a scriptwriter, Warne adapted Dr Paul White's "Jungle Doctor" fables for recordings, filmstrips and television. He wrote the radio drama "Encounter" which has been broadcast on over 70 radio stations throughout the world; created television commercials for Mortein, Pepsi and the Commonwealth Bank; and wrote and directed films in New Guinea, Thailand, Italy, Israel and Switzerland.

Warne taught Speech Communication at Moore Theological College for many years and lectured at the London College for Contemporary Christianity, the Moody Bible College Chicago and other colleges in Africa, Asia and New Zealand.

As an author, Clifford wrote many books ranging from children's stories to textbooks on communication. In the 1980s, he authored a number of children's books with Paul White. In 1988, He wrote the scripts for several Christian comics illustrated by Graham Wade.

Warne received an Australia Day honour (O.A.M.) in 1983 for service to religion through the use of media.