Dealmakers last week mourned the passing of Gavin MacDonald, Morgan Stanley's global head of M&A, who died Dec. 5 after suffering a heart attack a few days earlier in the firm's Canary Wharf offices in London. He was 47.

"He'll be sorely missed," says a colleague who worked with MacDonald daily. "He inspired you to go through rings of fire."

MacDonald spent his entire 25-year career as a dealmaker at Morgan Stanley, where he reportedly played a critical role in securing the $9 billion investment by Mitsubishi UFJ Financial Group Inc. last October that helped stabilize the firm. Described as calm and assured, MacDonald was known as a relationship banker who, along with Paulo Pereira, Simon Robey and Michael Zaoui, is credited with building Morgan Stanley's European business. His list of notable deals includes the merger of Thomson Corp. and Reuters Group plc, Akzo Nobel NV's purchase of Imperial Chemical Industries plc and the Toys "R" Us Inc. acquisition by Kohlberg Kravis Roberts & Co., Bain Capital LLC and Vornado Realty Trust.

MacDonald joined Morgan Stanley as a financial analyst in 1983 after receiving an M.A. in law from Cambridge University. Early on, he set out to create, along with John Studzinski, a European advisory group for the firm. The plan initially called for Morgan Stanley to advise mostly U.S. clients on their European deals, but by the late 1980s, it broadened as homegrown firms such as Kleinwort Benson Ltd., S.G. Warburg & Co. and Schroders plc were starting to recede. MacDonald became a managing director in 1997 and in 1999 was tapped to run Princes Gate Investors, Morgan Stanley's European merchant bank.

MacDonald returned to advisory in 2004, when he became a vice chairman, responsible for developing business in the food, beverage, consumer products, luxury goods, retail and utilities sectors. Two years later, he was tapped to head European M&A after Pereira bolted to join fellow Morgan Stanley defectors at boutique investment bank Perella Weinberg Partners LP. He took the helm of Morgan Stanley's global M&A effort last year, when Paul Taubman was named head of investment banking. It marked the first time Morgan Stanley's M&A group chief had resided in London rather than New York.

"Gavin was an extremely decent, universally liked, funny, selfless and deeply valued man," CEO John Mack wrote in an internal memo announcing MacDonald's death. "He was also a close and generous friend to many of us."

MacDonald leaves behind his wife Luise and family.

"We need more people like him," says a colleague.