In 1955, hailed as a teenage singing sensation, Hamilton began performing in nightclubs, and live on national radio. He guest starred on The Ford Show, Calling The Stars and The Gladys Moncrieff Show. He also had hit records with "Primrose Lane" and "The Things We Did Last Summer".

In 1956 Hamilton guest starred on Australia's first variety show broadcast on New Year’s Eve on ABC TV. Also in the 1950s, Hamilton featured in variety shows on all channels, including The Hit Parade (ABC), Make Mine Music (ABC), Bandstand (Channel 9), Sydney Tonight (Channel 7), and in the 1960s the seminal variety show Revue 61/62.

1960s Hamilton was in the undefeated World Champion Squash team. He competed for: NSW and Australia and Victoria from 1962-1970.

In 1961-62, Hamilton was a regular on the television show Revue 61/62, produced by MCA (America) for the 7 Network.

In late 1965, Hamilton compered In Melbourne Tonight on Monday nights on Channel 9.

From 1970 to 1972, Hamilton was the co-convener of the Australia Party. He headed the run for Parliament and his party was successful in having several senators elected. Upon Hamilton’s departure for America, the party provided the nucleus of the Australian Democrats, led for many years by Don Chipp. Hamilton was also involved in the "It's Time" campaign, along with Mick Young and Clive Holding.

Hamilton also devised and appeared in a TV commercial for the Philip Morris cigarette brand "Kingford". The commercial won the Logie award for Best TV Commercial in 1974, but resulted in Hamilton's dismissal from "Division 4", as his appearance violated a contract clause specifying that series regulars wouldn't appear in television commercials. He went on to host his own national variety shows on the ABC: Ted Hamilton's New Wave and Ted Hamilton's Musical World.

1975 because of his chairmanship of: The TV-Make It Australian Committee, the doors to Australian commercial television slammed. Hamilton was banned from Channel 9 by Clyde Packer, and informed that he would not be employed by the networks again, (he has not been employed by 7 or 9 since). Facing this restriction in a television dominated profession; Hamilton moved his family to the United States and established a successful acting and corporate career.

In 1980, when Rupert Murdoch attempted to establish a television presence in Australia, he acquired the Ten Channel in Melbourne. He invited Hamilton to return to Australia, to host The Ted Hamilton Show. However, the Broadcasting Control Board opposed his ownership and Murdoch quickly surrendered the idea, and sold his interest.

In 1981 he returned to the United States. He was appointed chairman of two US companies involved in the placement of private capital for films and corporations. He also served as a senior consultant to several national companies in the US.

In 2001 Hamilton returned to Australia, performing in music and acting.

In 2002 he performed in the international television series Guinevere Jones, playing the role of Merlin.

In 2011 Hamilton was appointed Australia Day Ambassador.

In the 2013 Australia Day Honours List Hamilton was awarded an OAM or Service to the performing arts and to the community.