Prior to this appointment on 15 January 2016 by United Nations Secretary-General Ban Ki-moon, Forsyth was the chief executive officer of Save the Children.

[3] While at Oxfam, he was employed alongside Kevin Watkins, who subsequently succeeded Forsyth as CEO of Save the Children.

Forsyth served as an advisor to Prime Minister Gordon Brown, and acted as director of strategic communication at 10 Downing Street from 2007 to 2010.

[10][11] Forsyth resigned from UNICEF on 22 February 2018, wishing to avoid "serious damage to our cause and the case for aid" that might result from his continued affiliation.

[12] After resigning from UNICEF, Forsyth founded North End Strategy, a communications and management consulting firm based in Oxfordshire.