Two months later, 47 years ago today, on Feb. 21, 1965, Malcolm X would be killed at the Audubon Ballroom, in New York.
But, on this emotionally charged night, he came to Philadelphia to discuss his new ideas on Islam and connections between the struggles of Africans and African-Americans.
"I'm happy to be here, Joe Rainey, honored and pleased," Malcolm X said to the radio host, a journalist who frequently had civil-rights activists on his show.
"This is one of the few programs that I could get on in this country and get an objective reception."
It would be a riveting discussion in which the controversial leader of the newly formed Organization of Afro-American Unity connected the struggles of African nations breaking away from colonialism with the struggles of black people in the United States to fight for equal rights.
The December 1964 visit occurred months after his second trip abroad to Mecca, the Middle East and Africa, and after he had renounced the former separatist, anti-white position that he often had been criticized for espousing in the past.
In his Autobiography, co-written with Alex Haley, Malcolm X wrote that after seeing Muslims of different colors sitting and eating together, he saw that true Islam was not a religion based on segregation by skin color or ethnicity.
"Never have I witnessed such sincere hospitality and the overwhelming spirit of true brotherhood as is practiced by people of all colors and races here in this Ancient Holy Land, the home of Abraham, Muhammad, and all the other prophets of the Holy Scriptures,' " he wrote in a letter quoted in the book.
"Even I was myself astounded. But there was precedent in my life for this letter. My whole life had been a chronology of - changes."
On his trip, he also met with heads of state in Egypt, Tanzania, Niger, Uganda, Kuwait and Lebanon.
"When we see that our problem is so complicated and so all-encompassing in its intent and content, then we realize that it is no longer a Negro problem, confined only to the American Negro; that it is no longer an American problem, confined only to America, but it is a problem for humanity," Malcolm X said.
"It is a problem for the world and it ceases to be a problem of civil rights and becomes a problem of human rights."
Although many people think that Malcolm's break with Nation of Islam leader Elijah Muhammad came after his trip to Mecca, the initial fallout happened in early December 1963.
That's when Elijah Muhammad suspended Malcolm for 90 days after controversial remarks about the "chickens coming home to roost" following the November 1963 assassination of President John F. Kennedy.
According to scholar Manning Marable's Malcolm X: A Life of Reinvention, Elijah Muhammad ordered his ministers to say nothing in public about Kennedy's murder, so as not to provoke even more harsh treatment of his followers.
But the 90-day suspension became an indefinite suspension, and by March 1964, Malcolm decided to break away from the Nation of Islam.
Even before his comments on Kennedy's assassination, there had long been death threats, not to mention his home being firebombed. Some thought that was because members of the Nation didn't like Malcolm's growing fame as a speaker.
He was frequently invited to speak at colleges. Only weeks before his last appearance at WDAS, Malcolm had taken part in the Oxford Union Debate, at Oxford University, in England, on Dec. 3, 1964.
Malcolm X had spoken on WDAS before, but not under such heated circumstances.
The Rev. Joe Williams, a former member of the Dixie Hummingbirds and now pastor of the Mount Airy United Fellowship, remembers talking with the station's disc jockeys about the interviews.
"They talked about how smart he was," said Williams, who recalled that the Dixie Hummingbirds were scheduled to sing at the Audubon Ballroom the night that Malcolm X was killed. "That was a very progressive station at that time, very progressive."
The station's ties to the civil-rights movement extended beyond Malcolm X, as showcased in a website created by Alexander, whose maternal grandfather, Max Leon, owned the station.
Her father and grandfather not only welcomed Malcolm X to be interviewed when other radio and TV stations banned him, but they also hosted other civil-rights leaders, including the Rev. Martin Luther King Jr., New York Rep. Adam Clayton Powell and Philadelphia NAACP leader Cecil B. Moore.
She said that the station would host "charity concerts" at Philadelphia's old Convention Hall and donate the proceeds to both organizations.
"When he [King] got killed, it was the only time I saw my father cry," Alexander said. "He ordered all programming suspended and we went wall-to-wall with gospel music. We had different community leaders and healers on the air intermittently talking about the loss and Dr. King's ideas. There were appeals to stay calm."
She said that a number of people gave the station credit for helping to keep Philadelphians from rioting after King's death as people did in other cities.