Ivanhoe Donaldson, 44, Mayor Marion Barry's closest adviser and confidant throughout the mayor's political life, was a hard-driving boss for most of the city government until he left for the private sector in 1983.

The gaunt former deputy mayor for economic development was known for his intensity and combativeness as well as his organizational skills, and he never seemed far from a political campaign throughout his stints in government service.

The radical outsider turned ultimate insider, Donaldson met Barry during their days in the civil rights movement in the 1960s and later became architect of Barry's successful 1978 campaign to oust an establishment mayor from the District Building and start a new era of politics in Washington.

An organizer for the Student Non-Violent Coordinating Committee in the South, Donaldson in the first Barry administration was given the task of shaping up the city's Department of Employment Services.

After managing Barry's second successful mayoral race in 1982, Donaldson served as deputy mayor for economic development during the second term. He left government in October 1983 and later became vice president of E.F. Hutton & Co. until he resigned in September.

Donaldson was as unchallenged in wielding power as he had been fierce in challenging power before he had it, according to associates. Much of this stemmed from the perception that when he spoke, it was with the authority of the mayor.

"He did a lot to pull together the many pieces of the city government so that there was a recognition that they all had to work in the same direction," John Tydings, executive vice president of the Greater Washington Board of Trade, said yesterday. "He was one of the brightest people I've ever dealt with, and tough when he needed to be tough."

Even those who have fought with Donaldson credit him with being smart, energetic and having an ability to get things done.

"He really did succeed in organizing and cleaning up that department," said Theodis (Ted) Gay, whom Donaldson beat in a hard-fought race for the chairmanship of the Democratic State Committee in June 1984. Donaldson stepped down as party chairman in June. In the campaign for the chairmanship, Gay said, "The big realization was that he was in a position to extract promises and make exchanges." But, he said, Donaldson "fought very fair."

Some knew Donaldson as the mayor's "hatchet man," and Barry did little to dispel that impression.

"He's done a lot of dirty work for me," Barry told well-wishers at a farewell reception for Donaldson in 1983. While relying on him to take tough positions, the mayor also said, "sometimes he gets on your nerves, including mine occasionally."

While in charge of economic development in the city, Donaldson was praised and criticized for deals he negotiated with developers in attempts to spur renewal throughout the District.

Donaldson kept out of the limelight when in government. He and his wife, Winifred, live on Wyoming Avenue NW and recently adopted a 5-month-old child.