Sheldon has been appointed to the new position of director digital at the Starcom unit Starcom Digital.
His appointment completes the senior management line-up at the division.
Matt Simpson, the head of digital, and the group account directors Martin Shaw and Richard Hollidge will report to Sheldon.
Sheldon has spent more than ten years at WPP, first as a founder of JWT Digital and then as the head of MindShare's digital activity.
In 2002, he took on the additional role of associate director at the WPP market research company The Henley Centre. He recently left MindShare to work as an independent consultant.
Reporting to Nigel Foote, Starcom's managing partner for Europe, the Middle East and Africa, Sheldon will head a team of 30, with £30 million in billings.
Foote said of the appointment: "Nigel Sheldon combines a unique set of skills as both a senior manager and a strategist, with unrivalled experience and acute client savvy.
"We're delighted that he is joining us during such a period of dramatic growth for Starcom Digital."