Who better to mastermind Ronald Reagan's last hurrah -- the 1985 inaugural that will launch his second four-year term -- than his resident genius of pageantry and the presidential image, White House Deputy Chief of Staff Michael K. Deaver?

Yesterday in Santa Barbara, President Reagan announced just that. Deaver, who has been with Reagan since his days in the California statehouse, will be general chairman of the 1985 inaugural committee, answerable to the president.

At the same time, Reagan announced that Washington, D.C., executive headhunter Ronald H. Walker, chief advance man in the Nixon White House and more recently manager of the 1984 Republican National Convention, will be the committee's chairman. He will answer to Deaver.

The president's announcement said that Deaver will have "supervisory responsibility for all inaugural activities and will report directly to the president."

In charge of the White House office of presidential scheduling, which also supervises the sections of presidential advance, military, first lady and public affairs, Deaver was the chief architect planning Reagan's trips abroad and his media appearances before and during the campaign. He also served as presidential liaison to the 1984 Olympic Games.

Robert Keith Gray, cochairman of Reagan's 1981 inaugural committee, saw Deaver's selection as a practical solution to an unusual situation. Because Jan. 20, the constitutionally designated date for presidential inaugurations, falls on Sunday in 1985, President Reagan will take his oath of office twice, the first that day in a private ceremony and again on Jan. 21 in an official public ceremony.

"Then, too, there is a difference in a second-term inaugural," Gray said. "With the president succeeding himself, many things can go on in the White House that are a part of normal working procedures. By choosing Deaver it places that emphasis in the White House."

Gray called Deaver "a good, creative fellow with immediate access to the Reagans," an important factor since he recalled that they approved of everything "from the design of the inaugural license plates on" last time.

Gray saw the choice of Walker as Deaver's top lieutenant to be his reward for running the GOP convention "just like a clock, so well that there isn't anything he couldn't have now." Walker is managing director and partner in the executive recruitment firm of Korn-Kerry International.

Calling the inaugural committee job "exciting but totally consuming," Gray said he and his cochair, United States Information Agency Director Charles Z. Wick, worked nonstop for 2 1/2 months starting immediately after Reagan's election.

Together, Gray and Wick masterminded the most expensive inaugural in history, a three-day spectacular that featured opening and closing extravaganzas and 107 inaugural balls around the country connected by satellite to those in progress in Washington.

"The people paid for it through their individual tickets, the government didn't spend a dime," Gray said. "Afterwards, we turned $1 million over to the foreign students exchange and also put aside $350,000 in seed money for the 1985 inaugural."

Even before American voters had chosen their next president, work on the 1985 inaugural was well under way. The Armed Forces Inaugural Committee, which began work last April, is coordinating 12,000 military personnel who will line the parade route, provide escort services, remove snow if necessary and lend medical assistance.

On Jan. 21, Reagan, for the second time in history, will take his oath of office on the west front of the Capitol, which looks up Pennsylvania Avenue toward the White House. Working since August on that aspect of the day has been a six-member congressional inaugural committee.