Jain takes on the role previously held by Zai Bennett, who accepted the position of controller of BBC Three late last year.
Reporting to ITV's director of programme strategy David Bergg, she will be responsible for the broadcaster's suite of digital channels - ITV2, ITV3, ITV4 and CITV.
Discussing her appointment, Jain said: "This is undoubtedly an exciting time to be joining ITV. ITV2, 3 and 4 are already some of the most watched digital channels in the UK and I can't wait to take the helm and work with Peter, David and their hugely talented team to build on this success."
Peter Fincham, ITV's director of television, added: "Angela has a very impressive background in finding hot new talent, having an eye for acquisitions that create a real buzz and delivering returning favourites time and time again.
"She is also one of the most talented commissioners in the industry today, nurturing new talent to bring original ideas to screen. I'm delighted that she'll be joining ITV to build on the success of our digital channels."
Jain left Channel 4 at the start of the year after helping develop a slate of hit shows for E4, including The Inbetweeners and Misfits, as well as acquiring US musical comedy Glee.
Under her guidance, E4 grew its audience share among 16 to 34 year-olds by 35%, helping the network win 'Channel Of The Year' at last month's Broadcast Awards.
Prior to working at E4, she was commissioning editor for factual entertainment at Channel 4 and deputy controller of entertainment at Channel 5.