Sharrocks, 47, is currently the managing director of Warner Brothers Pictures. His appointment comes a week after Aegis announced that Craze would be leaving after 15 years with the company.
Sharrocks assumes responsibility for Carat, Vizeum and Posterscope in the UK and Ireland and will report to the chief executive of Aegis Media EMEA, Jerry Buhlmann.
Craze was passed over for this job when it became vacant following the resignation of Eryck Rebbouh and Bruno Kemoun, who clashed with the Aegis plc chief executive, Doug Flynn. Rebbouh and Kemoun have since emerged as the heads of WPP's new third-string agency network, while it is not known what Craze intends doing next.
Sharrocks left Grey at the end of 1997 after seven years with the agency, including four years as the deputy managing director and chairman of MediaCom.
He stepped back from MediaCom in 1995, allowing Andy Troullides to take over as managing director.
In 1999, he resurfaced at Warner Brothers, an account on which he'd worked during his time at Grey. He is expected to join Aegis Media within the next two months.
Buhlmann said that Sharrocks has a good strategic reputation and that his experience of content at Warner Brothers would also prove useful in providing future direction for the agency.
He added: "Nigel is a great talent and his experience as a senior advertiser, and previously as a leader in media and advertising agencies, make him ideal to take our media operations forward in the UK."
Sharrocks said: "I know the Aegis media business well and believe that there are good opportunities to expand its market positions in the UK and Ireland. This is an exciting time to be joining the business and I look forward to bringing further impetus to it."
Last month, Aegis plc announced that its end-of-year group revenue for 2003 was up 9.6 per cent to £648.8 million. However, its agencies had a mixed performance.
In 2003, Carat saw long-standing big-spending clients, such as Cadbury, leave the agency. In January, Vizeum was also rocked by the loss of the £10 million RHM account.
However, this month Carat won the £9 million planning and buying brief for WH Smith and the planning account for Jacob's, worth an estimated £5 million.