In 1951, he was indicted by a grand jury in Baltimore in a numbers conspiracy and was convicted. The Supreme Court overturned his conviction in 1954 on the basis that he had testified before the Senate committee under a grant of immunity and his testimony could not be used against him in any criminal court.

Reflecting on his days in the numbers business, Mr. Adams explained in a 1966 interview with The Baltimore Sun, "I was too young and concerned with making a dollar. Anyway, in those days, lottery was considered a crime. If you got arrested, all you did was pay a fine. Still today, it's not a racket in the eyes of the people."

He added: "I am glad I was in the numbers business. I don't regret my past."

In 1980, Mr. Adams was charged with operating a $5 million-a-year numbers operation. He was found not guilty in 1984 in Baltimore Circuit Court.

When the Maryland State Lottery was established in 1973, Mr. Adams was hired as a consultant.

In 1940, Mr. Adams added to his ever-expanding business interests when he founded Adams Realty Brokers in the 1500 block of Pennsylvania Ave.

"I was always working for one object — to make myself some money and go into legitimate business," Mr. Adams said in the 1966 interview.

One such business interest was Parks Sausage Co. In the 1940s, Mr. Adams brought Henry G. Parks Jr. to Baltimore and the two men bought into a Cleveland sausage firm.

The men disagreed on an expansion strategy with the majority owner, and Mr. Parks, with Mr. Adams' financial help, moved to Baltimore, where he established Parks Sausage Co. In 1969, the company became one of the first black-owned companies to trade publicly on Wall Street.

Mr. Adams bankrolled Super Pride supermarkets, which was headed by Charlie Burns, a cousin of Thurgood Marshall's, Mr. Pietila said in an interview Tuesday.

African-American businessmen who turned to Mr. Adams for financial help had to agree to the condition that he would have a 51 percent stake in the business, no matter how small his personal investment.

"Willie is an unmeddling man," a business associate told Mr. Pietila. "You don't meddle with him, he don't meddle with you."

"I used to call him the Small Business Administration," said attorney and friend Larry Gibson. "I recall that he would typically make $25,000 loans to people who were operating grocery stores and liquor stores, maybe a record shop in the 1960s."

Mr. Adams' apparent Midas touch did not extend to everything in which he invested. He joined with his friend, boxing legend Joe Louis, in creating a soft drink, Joe Louis Punch. It failed miserably.

When Mr. Adams was 65, he told The Sun he was still energized by the thrill of businesses that required risk capital. "I'm still a businessman, and by the time I'm ready to die, who knows, maybe I will have lost it all," he said.

In the 1970s, Mr. Adams brought Theo C. Rodgers to Baltimore to work for Parks Sausage.

"When we sold the company in 1977, we formed A&R [Adams & Rodgers] Development Corp.," said Mr. Rodgers. "Willie had a profound impact inside and outside of Baltimore. There isn't a black-owned business in Baltimore that he didn't finance."

Mr. Rodgers helped Mr. Adams and his wife establish the William L. and Victorine Q. Adams Foundation, which helps city students who want to attend college and study business.

Mr. Adams' philanthropic interests included the NAACP, the United Negro College Fund, Liberty Medical Center, the YMCA, the Jewish National Fund and St. Francis Academy.

Mr. Adams and his wife, who died in 2006, lived for years in a house in Hanlon Park, near Lake Ashburton. For the past eight years, he had lived at Roland Park Place.

The cigar-chomping Mr. Adams enjoyed playing golf.

At Mr. Adams' request, his funeral will be private and by invitation only, Mr. Rodgers said.

Surviving are a daughter, Gertrude Venable of Emmitsburg; and a granddaughter, Trudy Venable of Dallas.

Baltimore Sun reporter Jacques Kelly and researcher Paul McCardell contributed to this article.