California Gov. Edmund G. (Jerry) Brown Jr. last night became the first candidate in the 1980 presidential race to make an open, personal appeal for the support of gay voters.

Appearing before a cheering crowd of more than 600 at a Washington gay disco, Brown pledged to bring the gay rights issue to the forefront of Democratic Party politics, and, if elected president, to work for a far-reaching agenda to promote gay rights.

Brown said he would issue an executive order banning discrimination against homosexuals in the federal government, work for passage of national gay rights legislation, and appoint qualified gays to federal jobs.

Washington gay activists considered Brown's appearance at the rally a breakthrough in itself.

Frank Kameny, introduced as "the grandfather" of the city's gay rights movement, recalled that until recently, politicians have shunned such events. "Frankly, you know you have arrived, you know you have reached the inner sanctum, when a major candidate for the presidency comes here," he told the crowd at The Pier, located at 1824 Half St. SW.

President Carter and Sen. Edward M. Kennedy (D-Mass.) sent emissaries to represent them at the event.

In a letter described as his strongest statement to date on gay rights, Kennedy said:

"When a qualified individual is denied employment or a financially able person refused housing because of his or her race or sex or sexual preference, then we must all be concerned. So, too, we must be concerned when an individual is denied permission to come into this country because of a statute based on outmoded medical and psychiatric views of homosexuality." o

The letter, read by Susan Estrich, the top-ranking woman on Kennedy's Senate staff, was loudly applauded.

The crowd was clearly disappointed that Carter decided to send Michael Chanin, a deputy presidential assistant, rather than a top-level aide. Chanin was loudly booed.

"What happened to Bella [abzug]? What happened to Midge Costanza?" one heckler yelled, referring to two top-ranking advisers on women's issues whom Carter fired.

Chanin told the rally, held to raise funds for a project to elect gay delegates to next summer's Democratic and Republican conventions. "You have in the White House a president who is meeting with you, a president who respects you."

He added, "I think we've made progress . . . we've begun to change the attitudes of people."

Brown's appearance was a recognition of the growing political clout of homosexuals, in this city and elsewhere. In recent years, gays have shown themselves as a major pool for fund-raising and volunteer workers for local candidates, including Mayor Marion Barry, who also appeared at the rally last night. Their support is sought with the same fervor as are other political power blocs, such as organized labor and blacks.

Earlier, at an airport news conference, Brown said he hopes gays will provide a source of campaign fund-raising for him.

After last night's rally, Brown attended a fund-raiser local gays had organized in his behalf on Kalorama Road.

Brown's reception here does not mean he has the universal support of gays, said Tom Bastow, one of the organizers of the $10-per-person fund-raiser at The Pier. "Gay people cover the spectrum of politics. I know a lot of conservative gays who support Ronald Reagan. Some more liberal ones like Kennedy."