In his rematch with Rep. Roy P. Dyson (D-Md.), Wayne T. Gilchrest billed himself as a veteran, a teacher and a family man. Now he can add a new role: philosopher-congressman.

Gilchrest, a Republican who reads Ralph Waldo Emerson and talks earnestly about Mother Earth, won the seat in the 1st Congressional District that Dyson and the Democrats had held for a decade. He received 56 percent of the vote, carrying 10 of 13 counties and cutting deeply into Dyson's home base of Southern Maryland. The district also includes the Eastern Shore, where Dyson captured only a couple of counties, and Harford County north of Baltimore.

"This shows what a positive campaign can do," said Gilchrest, 44, who portrayed himself as an integrity candidate. He spent a large part of yesterday with his wife and three children at their Kent County home and said he would begin today to work on putting together a staff and a district office.

The Gilchrest victory, after a 1988 loss to Dyson by 1,540 votes, was fueled by a last-minute infusion of money and support from an eclectic group of sources, including the U.S. Chamber of Commerce, the Sierra Club, the National Abortion Rights Action League and the National Rifle Association. As of last week, he had received about $55,000 in the final days of the campaign, putting the money to use in a barrage of television commercials. Vice President Quayle and four Bush administration Cabinet secretaries also traveled to the 1st Congressional District on Gilchrest's behalf, and President Bush telephoned him yesterday with congratulations.

The Dyson loss apparently did not, however, reflect the spirit of anti-incumbent fervor that many experts had credited with shaping the 1990 elections. In the other seven congressional races in Maryland, the incumbents all won reelection by healthy margins.

Dyson's vulnerability was apparently amplified by a spate of well-publicized problems: revelations about his conscientious objector status during the Vietnam War clashed with his pro-defense stance on the House Armed Services Committee, and there were questions about his link with defense industry consultants who were convicted in an investigation of Pentagon procurement practices. Also still fresh in many minds was the suicide two years ago of Dyson's chief aide, Thomas M. Pappas, after questions were raised about campaign funds and the management of Dyson's office.

Said Rep. Steny H. Hoyer (D-Md.): "Whatever the reasons for Mr. Dyson's defeat, they were particular to his district and not part of a general trend."

Gilchrest's status as a novice representative could make him vulnerable when the state's congressional districts are redrawn, a process that will begin now and continue until 1992. The state's Democrats will be in charge, and the 1st Congressional District is ripe for change.

But, in responding to speculation that he might be a two-year wonder whose district would be cut from under him, Gilchrest said that he is "not this country bumpkin schoolteacher that everybody perceives us as being."

"We have full control over everything we do," he said. "It is measured and well thought out. This is not an accident."