Port of Seattle Chief Executive Officer Mic Dinsmore has said he will leave his position early next year.

Dinsmore has been chief executive for 14 years, the longest tenure in that position in the Port's 95-year history.

Commission chairman Patricia Davis said the commission accepted Dinsmore's decision with profound regret, but understood his desire to open the next chapter in his life.

"He will be leaving an unprecedented legacy," Davis said. "Mic Dinsmore has forged consensus among commissioners, customers, labor and business leaders, diverse communities and elected officials to lead the Port of Seattle to unparalleled successes. He has carried out commission investment policies with drive, dynamism and creativity. His unique blend of business acumen and diplomatic skills have brought tremendous economic vitality to our region for many years, and spectacular results in the past two years. He will be hard to replace."

Although he is not retiring from professional life, Dinsmore, 61, said it is a good time to transition because the Port is on a trajectory to bring even greater financial and business results to the people of this region.

The Port will set records again this year in virtually every line of its business: passengers at Seattle-Tacoma International Airport, international container cargo and cruise operations.

In particular, Davis credited Dinsmore with leading the Port through the aftermath of the Sept. 11, 2001 terrorist attack in New York, which affected airports and seaports around the world. The Commission continued to make key investments in infrastructure, which have resulted in today's exceptional business climate.

The Port expects to see completion of the third runway at Sea-Tac by the end of 2008 and extension of Sound Transit's light rail to the airport by 2009. The airport opened a new Concourse A in 2004 and a new Central Terminal last year.

In the Seaport, Dinsmore oversaw development of three new container terminals, which led to double-digit growth in international trade in each of the past two years. His nurturing of extensive business and trade relationships in Asia foresaw the increase in trade with China, which is now the leading trading partner with the Port of Seattle. His tenure included redevelopment of a blighted and neglected part of the downtown Seattle waterfront, which now includes the Bell Harbor International Conference Center and cruise terminal, Bell Harbor Marina, a new Marriott Hotel, condominium buildings and a new Port headquarters.

The cruise industry, which did not exist in Seattle 14 years ago, now consists of more than 200 sailings a year for nearly 750,000 passengers. Each sailing brings an estimated $1 million into the local economy.

Construction projects are underway to rebuild Shilshole Bay Marina and docks at Fishermen's Terminal, and the Port Commission is considering opening another container terminal in the next two years.

Also, the Port has become a leader in environmental stewardship. Its developments include creation of 19 public parks and open spaces on the Elliott Bay waterfront, conversion of vehicles to natural gas and biodiesel, access for cruise ships to tie up to electric power while at shore, a groundbreaking agreement on wastewater discharges for cruise ships, and restoration of superfund sites in the Seattle harbor and Duwamish River. Airport construction projects resulted in creating a total of 178 acres of new wetlands.

Davis said the commission immediately will begin a nation-wide search for the new top executive. She said the search process will include soliciting public comments on the qualifications for a new CEO. Davis said the commission expects to select a new CEO by the end of the year.

Ideally, she said, the new chief executive will be in place in time to work in tandem with Dinsmore to achieve an orderly transition. Dinsmore said he expects to leave near the end of the first quarter of 2007.