Hunt, who left Channel 4 last month after seven years at the broadcaster, joins the Silicon Valley giant as it pushes an extended video offering, planning to spend $1bn (£750m) on original content next year. She will be the creative chief in charge of new programming.
The appointment of Hunt is the latest in a string of top-tier talent moves in the race to dominate digital video content, including Netflix's move to lure hitmaker Shonda Rhimes away from Disney's ABC.
Jay Hunt was most recently chief creative officer at Channel 4, but also served stints on BBC One and Channel 5, making her the only person to have led all three channels. She has been responsible for commissioning and developing some of the biggest TV hits of the last 10 years including Sherlock and Mrs Brown's Boys on the BBC and Humans, Gogglebox and First Dates for Channel 4.
She also pulled off the infamous poaching of The Great British Bake Off from the BBC, which gave Channel 4 its biggest night since 2012 and a host of advertising deals.
She had been tipped as the favourite to succeed David Abraham as chief executive of Channel 4 but resigned a few days before the final decision was made.