Richard Desmond, the owner of the Daily Express and Daily Star, has bought Five Group from entertainment network RTL for £104m.
The deal for Mr Desmond's Northern & Shell company to buy Five, which runs TV channel Five, has been closed with immediate effect.
RTL said a recovery in the UK TV advertising market meant now was a good time for it to sell.
Last month, Mr Desmond indicated that he wanted to buy the Sun newspaper.
"I am delighted to have taken ownership of the network, and know with the right investment, drive and leadership it can go from strength to strength as a competitive broadcaster and a modern player for the digital consumer," Mr Desmond said in a statement.
Dawn Airey, Five's chief executive, said she was "looking forward" to working with the new owners.
"Northern & Shell are an international media business with a prominent position in the UK.
"We now move forward under the ownership of a successful media company that wants to grow our business and has exciting plans for the development of Five."
Channel Five was first launched in 1997 and is home to popular Australian soaps Neighbours and Home and Away, as well as the Crime Scene Investigation series.
The channel was hit hard by the slump in advertising revenue during the downturn but the advertising market has picked up this year.
"With a significant recovery of the UK TV advertising market and Five performing well in the first half of 2010, we saw a window of opportunity to realise a transaction based on a fair evaluation of Five," said Gerhard Zeiler, chief executive of RTL Group.
Rival UK broadcaster Channel 4 was reportedly also interested in buying channel Five.
Richard Desmond has had a colourful and controversial career since leaving school at 14 with few academic qualifications.
By the age of 21, he owned his own house and two record shops, before acquiring the Express newspaper titles in 2000 with money he had made in the adult entertainment industry.
Roger Parry, the former chairman of Johnston Press who once made a bid for ITV, said Mr Desmond may be best known for his top-shelf publications but he will adopt an entrepreneur's approach to the channel.
"He is certainly colourful and has got a very high profile in Private Eye and other such magazines," he said.
"But I don't think you can necessarily judge his past in terms of guessing what he's going to do with channel Five.
"He's very cost-focused and on the surface at least very successful. Commercially the Daily Express and OK! magazine seem to have thrived under his ownership."