he celebration began hours before the end of an emotional five-month crusade to make a minister's son from Chicago's South Side the first black mayor of the nation's second largest city.

As soon as the first television projections of a Washington victory were made shortly after the polls closed at 8 p.m. EST, supporters of the 60-year-old lawyer leaped to their feet at a near South Side convention hall and chanted, "We want Harold. We want Harold."

"I feel great. I feel victorious. It was our time," said Edward Conrad Merritt, 33, a music teacher. "It's just like your birthday. You know you're going to get something . . . and your birthday finally comes."

"Black people will finally get a share of power in this city," his wife Ruth said. "Usually everyone is telling us what to do.

"Harold Washington brings dignity, pride and unity," said welfare caseworker Norma Wright, "and he makes me feel good all over that I'm black."

Nathaniel Clay, chairman of the grassroots voter registration movement that added 200,000 blacks to the rolls before the Feb. 22 primary, said, "The long evolutionary struggle of black people in this city has come to its fruition."

State Sen. Richard H. Newhouse, who had run for mayor as an independent eight years ago and received only 8 percent of the vote, said that Washington's election was a culmination of dissatisfaction with Chicago's machine politics that had been boiling for 20 years.

"It means the city of Chicago will finally get open government, will finally get fair government, will finaly get competent government," Newhouse said. "Every citizen of the city is immmediately better off today than he was yesterday."

The celebration for Washington at the Donnelly Exhibition Hall had much of the flavor of his campaign, with music blaring from a Caribbean combo on one stage, gospel singers on another, an Afro-Cuban jazz octet on a third platform, and a group of majorettes in still another part of the hall.

The crowd was a mix of black Chicagoans--many nattily dressed middle class and some not so stylish in windbreakers and dungarees. Many wore red, white and blue boaters plopped atop their heads and dozens of different Washington buttons.

Louise Benson, a unit director at a school for retarded children who was a Washington precinct worker, said many whites also shared credit for his showing. "You see a lot of white people wearing Washington buttons," she said. "I don't think as many white people are into that racist thing as the media would lead us to believe."

D.C. Mayor Marion Barry arrived late in the night, saying a Washington victory "means a great victory for the Democratic Party and the people of Chicago for reform."

Among the crowd of several thousand by that time were many of the 900 college students bused in by Operation PUSH, headed by the Rev. Jesse Jackson. Those who were registered voters had cast ballots for Washington. Others had canvassed in South Side precincts urging blacks to go out to vote.

Another group of visitors wore blue and white tee-shirts proclaiming, "Milwaukee for Harold Washington." They were among 50 people from that city, 90 miles north of Chicago, who also helped turn out the black vote here.

"Not only did he win for Chicago, he won for the whole nation. It let us know that blacks can work together," said Carol Stegall from Milwaukee.

Washington, a stocky former amateur boxer with gray hair that makes him appear fatherly, is divorced, lives in the integrated Hyde Park section, and is engaged to a teacher, Mary Ella Smith.

He followed in the footsteps of his father, Roy L. Washington, who was a minister, a lawyer and a precinct captain on the south side. He earned a law degree from Northwestern University and practiced law both privately and for the government.

When his father died in 1954, Washington replaced him as precinct captain and was elected president of the local Young Democrats. Eleven years later he was elected to the Illinois legislature, where he served 16 years.

In 1977 he ran for mayor, and made a poor showing. Three years later he was elected to Congress.

A cautious politician, Washington decided to run for mayor this time just five months ago--only after the huge increase in black voter registration.

His personal record quickly became a major issue. In 1970 his law license was suspended for five years for accepting fees from clients for legal work he didn't perform.

Washington also pleaded "no contest" in 1972 to charges that he had not filed income tax returns for four years. He was fined $1,036, spent 36 days in the Cook County Jail and paid $508.05 in tax arrears.

He repeatedly said during the campaign that his failure to file his returns was due to negligence and that he had been punished inordinately for the crime. To many blacks these were non-issues. Time and again he was described as a role model and qualified black professional and greeted at some gatherings as if he were a folk hero