The Canadian distribution company said its board had unanimously rejected the offer, which valued the company at 236p a share, "on the basis that it fundamentally undervalues the company and its prospects".
Shares in Entertainment One were up almost 10% to 217.5p in London at the end of Tuesday – meaning the company is valued at more than £900m.
As well as The Walking Dead and Peppa Pig – a hugely valuable property that is shown in at least 180 markets – Entertainment One owns more than 40,000 film and TV titles, including Spotlight, which won this year’s Oscar for Best Picture, and 45,000 music tracks.
The acquisition attempt is part of ITV chief executive Adam Crozier’s attempt to build "a global production business of scale", to help rebalance the broadcaster’s business model away from reliance on advertising.
But while ITV’s offer sits above the current share price, it is significantly under the value of the company last August, when shares were 292p. Since then, Entertainment One announced a refinancing plan that raised monthly interest payments, causing the share price to plunge.
Shares in ITV itself have rallied to 198.7p after they plummeted by almost a third in the four days following the Brexit vote.