Loesch, who helped create Fox Kids Network and has been involved in the development and production of such shows as "Animaniacs," "Smurfs" and "Bear in the Big Blue House," starts Aug. 17.
Loesch said the still-unnamed new company, a joint venture between toymaker Hasbro and Discovery Communications, will operate from Los Angeles and that she will be hiring about 50 people during the next year.
Maryland-based Discovery Kids will survive as an international brand but will cease to exist in the U.S. by about the middle of next year, replaced by the new joint venture.
On Thursday, Loesch notified the Hatchery, a family-media company she co-founded, that she will be stepping down as CEO in four weeks. She will finish her duties as executive producer of the TV movie "Christmas in Canaan,