Stuart Barber joined the charity four weeks ago from the British Heart Foundation where he was head of policy and public affairs.
Before that he was campaign and PR manager for homeless charity Crisis.
Barber said he wanted to make the organisation better known in the campaigning field and for the nationals to view the charity as the 'number one voice in children's cancer'.
The charity is keen to improve public understanding of the impact of surviving cancer in childhood.
Barber is developing a five-year press and PR strategy to advance its policy and campaigning initiatives and position CLIC Sargent as the authoritative voice in the field.
He leads a team of four - three of whom are new to the charity. Along with Barber, Kat Forse joins as senior press officer from Bristol-based agency Bray Leino. Two new press officers have also been hired.
Ruth Bowen joins from charity Sustrans, and Suzanne Palmer makes the move to PR having worked at the Bath Chronicle.