Ms. Reid had also always been captivated by politics. In the late 1990s she moved to Miami to write for a local television morning show. There, she became a fixture among South Florida lawmakers. She was involved in minority outreach for voter education and blogged. In 2005 she met James Thomas, a longtime disc jockey and radio veteran known as James T, who hired her to produce a talk radio show for listeners in the black community.

“I had to convince her of the power we had in radio in Miami,” Mr. Thomas said in an interview. “We were going to go to places people didn’t want to go.” This included Opa-locka, a town marred by gang violence and political corruption whose residents she interviewed. “We had Lou Dobbs on and Marco Rubio,” Mr. Thomas said, laughing, referring to the conservative Fox Business Network host and the Republican Florida senator. “She loved to debate.”

In 2011, Ms. Reid was named managing editor of theGrio.com, a news and analysis website aimed at an African-American audience. (By then she was also writing op-ed columns for The Miami Herald and appearing as a commentator on cable news.) Chris Witherspoon, now a correspondent for the movie ticket seller Fandango.com, was rewriting news briefs for the site when she arrived. “Joy said, ‘You are way too fabulous to be behind your desk,’” he recalled. She promoted him to entertainment editor.

When the singer Whitney Houston died in 2012, MSNBC called Ms. Reid to speak about it on camera, Mr. Witherspoon said. “Joy said, ‘I think you should do it,’” he recalled. He did so for a week and went on to appear on other talk and news shows. Ms. Reid, he said, “gave me my voice when I didn’t have one of my own.”

Despite a hectic schedule, Ms. Reid makes time for an extended family. “She is very girlfriend-y,” said Jacque Reid, a television personality who is not related to Joy but has been close with her for a long time. She remembered a party her friend, who lives in Brooklyn, had in December. There were some celebrities, sure. “She also had the women who helped raise her, her cousins and their children. Those are the V.I.P.s in her life.”

Ms. Reid got her television break in 2014 when she was hired by MSNBC to create a daily show called “The Reid Report.” It was short-lived, though, canceled the next year because of poor ratings (along with Ronan Farrow’s). “It was stressful because it was daily,” Ms. Reid said. “There was a lot more management eyes on us. And when it ended, you know, it was not fun. But it did enable me to do something I hadn’t done in my career, which was to actually be a field reporter.”