Sharrocks, who will also be responsible for the media agency in the Netherlands and the Nordic region, has been invited to Aegis's global executive board.
The promotions follow the sudden exit in May of global chief executive Mainardo de Nardis, who was replaced by Jerry Buhlman, the then chief executive of Aegis Media EMEA.
Other changes include the promotion of Marie-Laure Sauty de Chalon, currently chief executive of Aegis in France, to the new role of CEO of Southern Europe. This gives her responsibility for France, Belgium, Italy, Greece, Israel, North Africa and the Middle East.
Jose Luis de Rojas, Aegis's Iberia chief executive, has had Latin America added to his remit.
Aegis's communications planning head, Malcolm Hunter, has also been promoted to the new role of chief client strategy officer.
Buhlman said: "These promotions, which are richly deserved, will strengthen our business and ensure we have the best possible leadership team in place.
"The new regional responsibilities are a natural move and they reflect the balance of our business, with each cluster having critical mass and sharing some important cultural and market dynamics."