CACI International Inc.'s president of U.S. operations, L. Kenneth Johnson, will retire Nov. 1.

The Arlington government contractor said in a statement that the 58-year-old Johnson, its second in command, is leaving "to pursue personal interests and spend more time with his family and grandchildren." It said he would continue to work with the company as a consultant.

J.P. "Jack" London, CACI's chief executive, will take on the added title of president until Johnson is replaced. William M. Fairl, an executive vice president of the company, will become its acting chief operating officer for U.S. operations. The company will begin a search for a permanent replacement immediately, London said.

Johnson joined CACI in 1999 and led it in a number of recent acquisitions, including XEN Corp. and Century Technologies Inc. Johnson came to CACI from Federal Sources Inc., a McLean consulting firm. Before that he was a senior vice president at Tracor Enterprise Solutions, a Reston government contactor.

In fiscal 2003, Johnson drew a $322,500 salary, plus a $970,306 bonus.

"I know that he wants to spend more time with his family and young grandchildren, and I think he's just moved to that period of his life," London said, adding that Johnson was "like a duck in the water here."

CACI also said it is nominating Herbert W. Anderson, the retiring president of Northrop Grumman Corp.'s information technology unit, to its board of directors. Shares of CACI closed yesterday at $52.78, down 11 cents.