She will report to Francie Calfo, who has been promoted from president to chairman in recent days.
Falvey was most recently in charge of programming, development and production at M4, the proposed mobile video service US telco Verizon and kids content firm AwesomenessTV were working on before scrapping the plan in February.
Before that, she was head of comedy at Disney-ABC Television Group, and also worked in ABC’s international programming division.
Her appointment comes after former Endemol Shine North America co-CEO and chairman Charlie Corwin joined Imagine as chief executive in the first quarter of 2017, and after Anna Culp became executive VP of television.
Imagine has also secured a four-year coproduction and co-financing deal with US broadcaster CBS. That deal followed Raine Group investing US$100 million in Imagine last year.
Besides producing feature films such as Apollo 13 and 8 Mile, Imagine is known for TV series 24, Arrested Development, Friday Night Lights, Empire and Genius.
Director Howard and producer Brian Grazer launched the company in 1986.