Sir Martin Sorrell resigned over the weekend as leader of WPP. I wanted to pay tribute to a man who has reshaped the marketing services industry over the past 30 years. Here are a few of his achievements:

1. Developing Markets — He was early in appreciating the potential of China, Africa and India. His repeated trips to these markets created opportunities for Ogilvy and other agencies. This segment is over one-third of WPP’s revenue.

2. Research — As a numbers man, he saw that clients would increase spend only if it was proven to work. Kantar and Kantar TNS are the best in the business.

3. Horizontality — He understood that creative agencies did not have to be the leaders on every relationship. He brought the best of WPP to Colgate, Ford and many other clients without limiting the choice of personnel to a single operating company.

4. Scale Matters — He brought his media agencies together to become the most formidable force in the TV upfronts, and used this scale and power to secure better deals for clients and improve margins. And with the recent merging of Burson-Marsteller and Cohn & Wolfe, he created the third largest PR agency in the world, specializing in Brand, Corporate and Public Affairs.

5. Outspoken Advocate — He termed Google and Facebook "frenemies." He was always the one pushing for spend that builds brands. He was unafraid to speak with journalists at any juncture. He has been the most visible man in marketing.

6. Hustle — He is the most involved CEO. He went to every important global conference, unabashedly handing out cards and meeting new prospects. He intervened personally to keep clients and called CMOs to argue about reduction in budgets or lost brand assignments.

7. Imagination — Who could ever conceive of a $20 billion enterprise with 250,000 people. There was always the next deal to do, the next client to win, the new sector to enter.  There is something of the polar explorer in Sir Martin, a sense of destiny.

The industry will miss his always on, eternally present persona. He could be tough on his people and difficult with his competitors. But he has made a singular contribution in achieving recognition for our industry as a business to be reckoned with, a solid investment vehicle and a unique partner in building brands. Sir Martin Sorrell, here is to a job well done.

Richard Edelman is president and CEO.

Francois G. Durand / Getty Images