He replaces Dame Sheila McKechnie, who died in January following a long battle with cancer after nine years at the forefront of consumer rights.
Vicary-Smith came to the merged CRUK in 2002, via the Imperial Cancer Research Fund, where he had been director of fundraising and communications since 1996.
His departure means that only Dr Trevor Hince, executive director of research management and planning, remains fromthe six staff who led CRUK through the merger, and he is due to retire on 16 September.
Other former board members who have left this year are Susan Osborne, who was director of communications for eight years, and David King, director of corporate resources, who was interim director last summer. He becomes Samaritans chief executive later this month.
"I'm not surprised they've all gone on to large organisations, because the two charities had a lot of good staff," said one former colleague.
"All the merger books say it's good to get out the old guard to stop them criticising the newcomers, but the grassroots might feel that the charity it knows is changing too fast. They must have concerns about continuity."
Before joining the Imperial Cancer Research Fund, Vicary-Smith was head of appeals at Oxfam, and before that a management consultant at McKinsey's.