The IPA and ITV said they were encouraged that the Ofcom chairman, Lord Currie, had appointed someone with knowledge of the media and advertising industries.
Jim Marshall, the chairman of the IPA media policy group, said it was pleasing that Ofcom resisted the temptation to employ a Whitehall bureaucrat, and had got someone with experience of the market.
A Channel 4 spokesman said: "We hope he will be as even-handed as possible and that he develops a firm understanding of how the commercial TV market works so he can adjudicate in any disputes."
Ofcom replaces the Independent Television Commission, the Broadcast Standards Commission, Oftel, the Radio Authority and the Radio Communications Agency.
Carter takes over responsibility for ensuring that broadcasters fulfil their public service remit, overseeing taste and decency issues, and that there is competition in the media and telecoms market.
However, other industry observers were less effusive with their praise, amid some concern that Carter's experience as the chief executive of the ailing cable company ntl may prejudice his impartiality. One broadcaster said: "All I know about Carter was that he once ran a bankrupt cable company."
Patricia Hodgson, the chief executive of the ITC, had been considered a front-runner for the job.
But she said: "Stephen is an excellent appointment for Ofcom. The ITC will do all it can to support him to get Ofcom up and running."