It was Walter E. Fauntroy, the District of Columbia's congressional delegate, who called a press conference to announce that he and others would meet with the Palestine Liberation Organization's U.N. observer in support of U.N. ambassador Andrew Young's efforts to communicate with both sides in the Middle East conflict.

But the Walter Fauntroy who whisked through talks with diplomats and meetings with the press here today was a man changing many hats -- that of a politician, a Baptist minister, a delegate to Congress and, most importantly, a self-described disciple of the late Dr. Martin Luther King on his quest for a nonviolent solution to Middle East strife.

"I am a disciple, without question," Fauntroy said today aboard an airline shuttle bound for New York. "Neither Andy Young nor I nor other members of the SCLC (Southern Christian Leadership Conference) apologize for searching for the relevance of Martin Luther King's policies in the international political arena.

"I believe he is the single most important man with the single most important message, and that is that we have to find nonviolent solutions to the problem."

In the Washington that Fauntroy left behind, there was uncertainty about this high profile role of the city's sole congressional representative in the continuing controversy following the resignation of Young last week.

Some Jewish leaders and Jews active in city politics and close to Fauntroy were uneasy about his contacts with the PLO.

Others in Washington expressed concern that Fauntroy's actions might invite a backlash against the District of Columbia in Congress or further cripple an already foundering drive for ratification by state legislatures of an amendment granting D.C. full congressional voting rights.

Fauntroy indicated that he was aware of the concerns. "People are saying what do ministers know about the Middle East affair and why are they getting involved? I have received calls of support and calls of misunderstanding, people asking, 'what am I doing?' Some people think I'm trying to negotiate a settlement, but we are not trying to do that, we are trying to open up communications with all sides."

Fauntroy said that the SCLC, in addressing the needs of black Americans, has changed its focus from strictly civil rights to a consideration of other issues that affect not only blacks but other minorities. He said that the change in focus has been going on for quite a while, beginning in 1967 when Dr. King called for peace negotiations in Vietnam and later for recognition of Communist China.

"A sizeable segment of the black community has recognized the interrelated nature of domestic and international affairs for years. We as blacks have a high stake in this issue because no matter who starts the [Middle East] conflict, it is going to send shock tremors through the Western world, and black people in the United States, the last hired and the first fired, will be the hardest hit. When America is in a recession, black America is in a depression."

Fauntroy said that if black leaders are successful in opening communication with the PLO and the Israelis that black leadership would gain "the kind of respect in international affairs that we now give Martin Luther King posthumously."

"Prior to the time of the resignation, we thought Andy Young was handling it," said Fauntroy, long-time friend of Young, one of the founders of the SCLC.

"When we heard of Andy's resignation," Fauntroy said. "I was shocked and hurt, and filled with indignation that this should happen. Andy's resignation caused many of us to become attentive to the situation in the Middle East. Andy needs help."

Meanwhile, in Washington yesterday, two prominent Jewish community leaders and some Jews active in local politics wrestled with the possible impact of Fauntroy's actions. One Jewish leader said flatly that Fauntroy was wrong for meeting with the PLO.

"I don't think a responsible congressman should have any truck with terrorists," said Rabbi Stanley Rabinowitz of Adas Israel Congregation in upper northwest Washington. "I don't think my elected congressman should have anything to do with people who advocate terror as a political method."

Rabbi Joshua Haberman of the Washington Hebrew Congregation, the city's largest, said he was not offended by Fauntroy's meeting with the PLO. "Congressman Fauntroy didn't make a statement that he would not talk to the PLO. The State Department did," Haberman said.

Giant Foods Chairman Joseph B. Danzansky, a close political ally of Fauntroy and who is Jewish, was willing to give an old friend the benefit of the doubt. "Walter has a right to do what he thinks his position entitles him to do," Danzansky said. "I can't react to it until I see what the result is.

"I'd be very shocked if there were any trace of anti-Jewish feeling. I have confidence in him as a human being."

Meanwhile, City Council member John A. Wilson said Fauntroy's journey into foreign affairs could have an adverse impact on his constituents, who are greatly dependent on Congress.

Fauntroy has played an integral part in the effort to secure full voting representation in Congress for the District of Columbia. Yesterday, the head of one of the organizations working for national ratification of a constitutional amendment granting that representation, said a rift between blacks and Jews could fracture the base of that movement.

Jews have played a key role in the effort, said Richard Clark of the National coalition for Self Determination, and are an integral part of the traditional civil rights coalition that is one of the major bases on which the movement is built.

Mayor Marion Barry said yesterday that he has had no discussions about a possible deterioration of black-Jewish relations in the District of Columbia and did not think Fauntroy's efforts would jeopardize the full voting representation drive.

"Those people who are opposed to voting rights are going to be opposed no matter what he does," Barry said.

Barry also said that he probably would not attend a summit meeting of black leaders scheduled for Wednesday in New York because he is too involved in preparation of the City's budget for the 1981 fiscal year.