The agency picked up the business following a final shootout against Adam & Eve in a process run through the intermediary Oystercatchers.
Bartle Bogle Hegarty and Rainey Kelly Campbell Roalfe/Y&R were also involved at an earlier stage, however RKCR/Y&R withdrew from the process in August, while BBH was eliminated from the running last month.
YouView is expected to launch in the first half of next year, and will offer consumers a subscription-free set-top box that will provide a number of digital channels as well as a range of on-demand, interactive and catch-up services.
CHI & Partners will now be responsible for handling all of the launch advertising for the venture, with a total of £50 million expected to be spent on marketing and brand development in the first four years.
YouView's media agency review, also through Oystercatchers, is ongoing.
Backed by broadcasters BBC, ITV, Channel 4, and Five, as well as internet service providers BT and TalkTalk and transmission company Arqiva, YouView has had to fend off strong opposition from Virgin Media and Sky as it pushes forward with its launch plans.
Earlier this week, Ofcom announced that it would not investigate complaints from the two companies that YouView is breaching the competition act, citing that it would be premature to open an investigation "at the current stage of YouView’s development".