He replaces Andrew Newman, former controller of entertainment, who quit last month (PRWeek, 17 October).
The features element in Frow's role is new, and he is expected to concentrate on the key prime-time elements of the schedule, particularly the 8pm and 9pm slots.
Controller of youth and music Sham Sandhu heads the station's entertainment output until Frow starts.
Frow will report to five director of programmes Dan Chambers, who was himself appointed only two months ago.
In a statement, Frow talked about the need for 'a fresh challenge' and 'new opportunities', although details of his plans for the channel have not been revealed.
Frow took up his current role at Channel 4 last year.
His track record at the channel includes programmes such as Jamie's Kitchen, How Clean Is Your House?, Location, Location, Location, Nigella Bites, French Leave, River Cottage Forever, Sex Tips for Girls and No Going Back.
Previously, Frow was head of features at Channel 4, which he joined as editor, leisure and deputy commissioning editor, features, five years ago. Before that, he was an executive producer working across a range of leisure series at BBC TV.
Chambers was previously head of factual at five and is a former science editor at Channel 4.
Science, arts and history are to become key parts of five's programming as the broadcaster attempts to move its schedule upmarket. five is trying to move away from the sport and adult content which used to be its staple.
Chambers replaced Kevin Lygo, who moved to Channel 4.
five chief executive Jane Lighting, who joined the channel in April, secured an eight per cent rise in programming budget to £170m per year from owner RTL.