The Big Apple hat always sat to the left of musician Donny Hathaway's full, graveled face. The brim's tilt indicated not only his jaunty spirit and his identity with the blockboys, but his restless quest for fame.

The fame he sought arrived quickly, perhaps too early for the sensitive, shy Hathaway. In the early '70s, his popularity soared, then his career, and his emotional outlook plummeted. There was a long silence. In the last year, however, Hathaway was bouncing back and working, good signs that left his friends baffled about his fatal plunge last weekend from a New York City hotel.

Eight years ago, after his initial popularity at Howard University and Washington super clubs, success seemed to be his. When his first album, "Everything Is Everything," came out, Carole King bought eight copies. Aretha Franklin and Ray Charles noted the new competition and proonounced him "bad." Steven Stills wanted the 25-year-old, as did Roberta Flack, Curtis Mayfield and Jerry Butler.

Yet Hathaway, who will be buried in St. Louis on Sunday, was never satisfied with his own performance or what acclaim the music world gave him, a tension that caused long periods of withdrawal.In 1972, teamed with Flack, Hathaway won a Grammy Award, and he was sought after as an arranger, writer and producer. Here the classic overnight success story turned into the classic coping with fame saga. He was hospitalized twice that year for emotional problems.

While the decade for black male vocalists belonged to Stevie Wonder, Isaac Hayes, Al Green and Marvin Gaye, Hathaway developed his own following for his raw voice and versatility. When his performances became ragged, people spoke of the erraticism sadly. Then last year, after an absence of three years, Hathaway, now 33, began a return. Again with Flack. Last week they were nominated for a Grammy Award for their vocal duet, "The Closer I Get to You," and he spent last week working with Flack on three songs.

"After the reception for 'Closer,' Donny became convinced people were ready for him again. Before that he would say he wanted to wait until 1980 to do anything," Roberta Flack said yesterday. In the recording studio last Friday and Saturday, she said, "he was very up. A person who is truly depressed can't function. At one point he said, 'Let's break, I want to write some things down,' and he went to the piano and worked for a while. He was beginning to come out of the lull."

A dinner of fish, rice, salad and spoonbread at Flack's apartment followed the studio session. "After dinner I dropped him off at the hotel, and he asked if I had any more of the cake my housekeeper had brought back from Jamaica. I said, 'No, you guys ate it up but she would make some more,' and he smiled and said, 'That was so good.' I don't believed he jumped because a long time ago people in a hotel had complained about his playing the piano and singing. So often he would go to the window and sing. I think he fell."

Like many of his friends and fans, Flack painfully witnessed the ups and downs. At one of his last engagements in Washington -- at the Cellar Door in November, 1976 -- the musicians played one tune and Hataway another. Some of the patrons demanded their money back and the police were called. "He was really depressed," remembered Washington arts activist and promoter Tony Taylor. "I talked to him backstage and he remembered me. Then the musicians started arguing about how he had ruined the gig. He just got real quiet."

The depressions, said Flack, were a result of a talented man's frustrations. "He was very sensitive, reacting to the things around him, and whatever was inside of him. He was a genius, so he wasn't satisfied with his own performances, his own output. Like many creative people, his good periods were very exhuberant and his lows were extremely low."

In his lifetime Hathaway repeatedly heard himself called a genius and that might have caused him to set his hopes too high.He was born in Chicago but grew up in St. Louis with his grandmother. Her church and gospel singing quickly became the focus of his life. He started performing when he was 3, detouring onto the high school wrestling team but eventually choosing a music career. In the early 1960s Hathaway arrived at Howard University, with one black suit and a music scholarship, and the notion that his gospel background and the school's classical music emphasis would make him unique.

The restlessness was apparent. "He wanted to go, he wanted to say something new," recalled Leroy Dorsey, a voice professor. "He was sensitive, a person who would not sit down and talk about his plans but also had a lot of things on his mind."

Yet, Hathaway, who at 5-foot-8, frequently ballooned over 250 pounds, also had a lighthearted side. When he pledged the Alpha fraternity at Howard, the Alphas had the sharpest lyrics, the higest steps. "Donny was really well-liked," said frat brother Wisdom Coleman. "When he pledged, we made him play the piano a lot. Once I made him play all night for my girlfriend and me, but I wanted to make sure nothing happened to his hands."

Eventually, because his musical skills were attracting attention in the local clubs, Hathaway dropped out of school. Along with the old Murphy's Supper Club and Mr. Henry's, Hathaway played the old Bohemian Caverns. "On Monday nights I would bring in a trio and he begged for a job. I told him the best I could do was $10 a man," recalled Tony Taylor.

The next day he called back and said, 'Brother Taylor, if you could get me $12.' The bookkeeper said no. But when I went on the first tour with him and Roberta, he would tease and say, 'Hey Brother Taylor since you can afford $12, why don't you take it out of this $1,000 bill."

After Hathaway had spent a brief time at Chess Records with Curtis Mayfield, King Curtis heard him at a trade convention and introduced him to Jerry Wexler, the producer who touched Aretha Franklin, Ray Charles and Otis Redding.

Fran the factory at Atlantic Records came a gutsy, pounding sound that never lost its seductive sweetness. "Everything Is Everything" became a theme, "You've Got a Friend" a love song, "The Ghetto" an urban cry and "Someday We'll All Be Free" an anthem. By July, 1973 he had six albums, had closed the Newport Jazz Festival with Franklin and Charles, had composed the score for "Come Back Charleston Blue" and sang the theme for the television series, "Maude."

"Working with him was an experience, he always came with a fresh idea," said Arif Mardin, producer of three of his albums and last week's session with Flack. "He had written 'I Love the Lord' for a symphony. We had 25 strings, woodwind and brass in the studio that day and the music came out like Ravel and Debussy.Last week his talent was sharper than before."

All the time he was tormented because he didn't think the public liked him as much as Stevie Wonder or Al Green. He dropped out because he didn't think there was room for everybody. His marriage broke up. "And I kept urging him to work. He was doing a black symphony and one night called Quincy Jones and played it for two hours on the phone," recalled Flack. "Everywhere I went, Poland, Japan, Jamaica, people would ask for Donny. I told him that and he was scared to do 'Closer' but that brought back his confidence."

In the last four weeks, he wrote a song for Flack, called "Lift My Spirits." "It was very uptempo," said Flack, singing some of the words. "It was church. There are a lot of us who are black musicians and who are trained and move away from black naturalness. Donny was not interested in crossing over, under or beyond.He had that natural thing."