Andrew Corley Jr. was both proud and awed by the sight of legions of men, wearing the purple and gold colors of his fraternity, coursing through the halls of the Washington Convention Center on Friday.

And it wasn’t just because so many brothers of his beloved Omega Psi Phi, one of the nation’s oldest African American fraternities, had come to his city to celebrate its 100th anniversary. It also was that when Corley came to Washington in the 1940s, you didn’t see very many black men downtown at all.

“It. Blew. My. Mind!” said Corley, 88, whose eyes twinkled behind his glasses.

At a breakfast ceremony a few hours earlier at the convention center, he wore his ceremonial gold tunic, trimmed in purple, and was honored for his 70 years of service in the fraternity. His son, Richard Corley, 50, who became a member of the fraternity in 1987, snapped pictures with his iPhone as his father received a standing ovation.

Later, at the elder Corley’s home in Brookland, grandson Richard Jr., 21, a newly minted Omega man, would arrive with a half-dozen of his fraternity brothers from Morehouse College. “Look at those shoes!” Andrew Corley exclaimed, pointing to the work boots, spray-painted gold with purple laces, that some of the young men were wearing. “Those shoes are tough!”

For Richard Corley and his son, it was never a question of which fraternity they would join. But when Andrew Corley pledged Omega Psi Phi at the age of 18, major black fraternities and sororities were still relatively new organizations. Over time, they would gain widespread popularity and boast rosters of distinguished members. Notable Omega brothers include Langston Hughes, Bill Cosby, Vernon Jordan, Jesse Jackson, astronaut Guion Bluford, former Virginia governor Doug Wilder, and NBA stars Michael Jordan and Shaquille O’Neal.

Still, personal ties, especially among family members, are perhaps the strongest incentives for young men and women to select a particular black Greek-letter organization. Omega Psi Phi was founded Nov. 17, 1911, at Howard University, the first black fraternity founded at a historically black college. Alpha Phi Alpha, the country’s first black fraternity, was founded in 1906 at Cornell University in New York. The second one, Kappa Alpha Psi, was born in January 1911 at Indiana University.

Andrew Corley, who grew up in South Carolina, didn’t have a male family member who belonged to a fraternity. He chose Omega Psi Phi because his high school English teacher, whom he revered for his “very precise” elocution, was a member. Corley went off to South Carolina State University excited about pledging the fraternity.

“I was surprised because I did not expect the hazing,” he said, declining to be specific about what his brothers did to make him prove his mettle. It was worth it. Through the years, he said, “I found a lot of brotherhood, people who I could turn to in case I needed guidance.”

Corley was drafted into the Army out of college and fought in Guam during World War II. After his discharge, he came to Washington to attend Howard University.

“When I came here, segregation was at its worst,” he said. “You couldn’t ride in Yellow Cabs or Diamond Cabs, and you didn’t go downtown.”

He found work in the federal government, which eased hiring practices earlier than the private sector. Corley worked for the U.S. Postal Service for three decades, before striking out on his own in real estate.

In 1972, he sought to buy property on 14th Street NE that was owned by Robert C. Weaver, who in 1966 was appointed the first secretary of Housing and Urban Development by President Lyndon B. Johnson, becoming the first African American to hold a Cabinet-level position.

Another buyer had offered more money for the lot, which included the house where Weaver grew up. But Weaver was an Omega man. A historical plaque now sits outside Corley’s home.

Richard Corley got a degree in chemical engineering from Howard University in 1982. But he didn’t join Omega Psi Phi at the storied black institution.

“Howard was the founding chapter. It was very competitive. You might get 100 pledges for 10 spots,” said Richard Corley, who works for the Maritime Administration. So after college he pledged a professional chapter, commonly called a “grad chapter,” in Charleston, S.C.

It feels good, he says, to be a part of “an organization that we can say that we own and that working together as men we can build a community.”

Richard Corley grew up in a District that had become known as Chocolate City as a result of white flight following the riots of the late 1960s. By the time he started school, most of the District’s educational institutions had become predominantly black. Still, his was a middle-class upbringing with an emphasis on education and the principles of his father’s fraternity: manhood, scholarship, perseverance and uplift.

He marvels at the toughness of men of his father’s generation. “They had to fight against all the odds. . . . Their opportunities were not so plentiful, but they were able to stick to the task and get a lot of things done.”

His son, Richard Jr., is going into his senior year at Morehouse. An economics major, he has his eye on law school. He became a full-fledged member, or in black Greek parlance, “crossed over,” in April.

“It’s great to be a part of the legacy,” he said.

Did he even think about pledging another fraternity? “No,” he laughed. “I think I would have been put out of the house!”

The fraternity offered Richard Jr. an added bonus: “I’m the middle child of three. I have two sisters. Now I have nine new brothers,” he said referring to the young men on his pledge line.

“And I have nine new grandsons!” sang his grandmother, Angie Corley.

Richard Jr. went to Morehouse because his high school, Banneker Academic, was across the street from Howard University and he wanted to go somewhere new. But he loves his home town, he said, “because of its diversity — black, white, Hispanic.” A city that still has its racial divisions, it is far removed from the Washington his grandfather first encountered in the 1940s.

But, like his grandfather, he also is awed seeing all of his fraternity brothers “taking over the city . . . purple and gold on every street corner.”