Retired businessman Otis Warren Jr. is stubborn and proud of it. He doesn’t take no for an answer or let anyone tell him he can’t do something.

This steely bull-headedness helped him break barriers in Baltimore’s exclusive real estate and development world where often there seemed to be no room at the table for him or other African Americans.

He beat out the likes of the Rouse Co. and other powerhouse firms in the ’90s to win a contract with the federal government to construct a downtown office building, but then he couldn’t find anyone to finance it. Nearly 100 banks and investors blamed the slow economy and his lack of experience with big commercial projects for not stepping forward, despite guaranteed income in the form of a 10-year lease commitment from the General Services Administration. Race, Mr. Warren believed, also played a factor in his rejections.

Near collapse on several occasions, the project caused so much anxiety that Mr. Warren was once rushed to the hospital, believing he was having a heart attack brought on by the stress. Though at times he felt the project might kill him, two things kept Mr. Warren going: the idea of failure and the desire to make history and become the first African American to construct an office building in Baltimore.

Persistence eventually paid off. With the government threatening to give the contract to someone else, Mr. Warren bought out his two partners and brought on a firm with government contracting experience that could finance the beginning of construction. Mayor Kurt Schmoke, the first African American elected to that office, worked out a deal for the city to lease the building when the General Services Administration commitment ran out. Then the Maryland Industrial Development Financing Authority agreed to issue the bonds to finance the project. The $38 million, 11-story Crescent building opened in 1993.

“The business can take a lot of you,” Mr. Warren says. “You have to believe in yourself and be determined to make it happen.”

He would beat the odds time and time again, building an apartment complex near historic Dickeyville despite opposition from residents, some of whom Mr. Warren says worried it would bring too many black residents to the neighborhood. He became the first black president of the Greater Baltimore Board of Realtors in 1982, an organization that once banned his father from joining.

“He was a pioneer in terms of real estate,” says Stanley Tucker, president and CEO of Meridian Management Group Inc., a professional asset manager for economic development and private equity funds. “He had a tremendous business acumen and is a man of his word. If Otis told you he was going to do something, he was going to do something.”

J. Howard Henson, the former chief financial officer of the NAACP worked with Mr. Warren when the civil rights organization was relocating from New York to Baltimore, and they quickly became lifelong friends.

“I was around when he was pulling his hair out and sweating,” Mr. Henderson says. “When he was trying to figure out where to get the money from and all that stuff. He always stuck it through.”

Mr. Warren learned about running a business from his father, Otis Warren Sr., who didn’t finish high school but owned a night club, ice cream store and real estate firm. The elder Warren made his son, the youngest of three children, earn everything. There was no easy ride in the Warren family.

Mr. Warren retired 15 years ago and now lives in a gated community in Palm Beach Gardens, Florida, where he said the weather is better than his native Baltimore. He plays a little tennis, but mostly relaxes.

It’s time for the next generation to take the reins, he said.

“He didn’t want to be the first and only one,” Mr. Henderson says. “He wanted to bring others into the business.”

His son, Otis “O.T.” Warren III, now runs the business. Mr. Warren tries not to interfere but sometimes finds it hard. His son has a different business style and isn’t stubborn like he is.

“He is doing a good job,” Mr. Warren says. “I try to stay out of his hair.”