Some standups without a background in the collaborative work of sketch performance have struggled on “S.N.L.” Morgan found success early on, perhaps because he has none of the stereotypical standup comedian’s hangups about performing material that other people have written. As he reminded me, the source of his uniqueness as a performer isn’t the content of his jokes. “It’s not about material,” he said. “It’s just being funny. Anybody can get material, but you’re either funny or you’re not.”

Tina Fey told me, “I remember early on realizing that, the kind of funny Tracy is—just, you can’t teach it, and you can’t buy it.” Fey arrived at “S.N.L.,” as a writer, a year after Morgan. Some of the actors, she noticed, were sticklers about each beat of the sketches in which they appeared. But Morgan “just kind of breezed in and charmed the room,” she said. “I don’t think his hands have ever typed a sketch on a keyboard. When he would say something at the table, or when he would roll out in front of the audience, you could feel that they were predisposed to like him.” She added, “Some people have that, and the rest of us—it takes years for us to build the audience’s trust that we’re allowed to be talking. You could just feel people sit up and be, like, ‘Ah! This is gonna be funny!’ ”

“Tracy’s not someone you go to for precision, necessarily,” Fey continued. “It’s not race-based,” she added, tacitly acknowledging how easily these stylistic categories might slide into racial observation. “There’s a lot of white actors that I would also not go to for precision—they’re more visceral, they’re more . . . they feel it in the moment.”

One of the first things that Fey worked on with Morgan was a sketch in which he played the TV personality Star Jones, who is best known for her work on “The View.” “It’s not a great source of pride that one of my most successful things I did with him was put him in drag,” Fey said. “There should have been a female African-American—or three or four—there to do it.” Morgan didn’t have a Star Jones impression. The sight of him in a dress just made people laugh.

Morgan threw parties after the after-parties that “S.N.L.” has long been famous for. “They were sometimes in, like, a makeshift illegal casino, in an empty loft, and there were women there, serving drinks—women in thongs,” Fey said. “He’d be, like, ‘You gotta come to my party!’ ” By then, Morgan writes in the memoir, he had begun rolling with a rather large entourage. “I had this felon named Young God around me, I had Pumpkin, I had motherfuckers named Guilty all around me.” He felt less comfortable around his castmates. “I had my finger on the pulse of urban comedy, but when I brought my act to ‘S.N.L.’ those motherfuckers just felt bad for me,” he writes.

After Fey left “S.N.L.,” she pitched a TV show to Kevin Reilly, then the president of NBC’s entertainment division—and now, incidentally, the president of TBS, home to “The Last O.G.” The concept was for a sitcom set at a cable-news channel which played the tension between a liberal producer and a conservative pundit for laughs. Reilly suggested that she write something set at a place like “S.N.L.” instead, and, almost immediately, Fey thought of Morgan. Adding a “rich movie-star version” of her former co-worker could, she realized, make for a more complex arrangement of non-convergent world views. On “30 Rock,” Fey played Liz Lemon, the put-upon head writer of “T.G.S.,” alongside Alec Baldwin as Jack Donaghy, the semi-sociopathic NBC executive who is Lemon’s boss, and Morgan as the hammy and self-centered Tracy Jordan, whom Donaghy hires as the new face of Lemon’s show—led, to that point, by a pretty, blond star, played by Jane Krakowski.

“I was just young enough—just by a minute young enough and foolish enough—to not realize how potentially insulting that could be,” Fey said, of her characterization of the over-the-top Tracy Jordan, which skimmed perilously close to her perceptions of Morgan. The character was also based, in part, on other black comedians, like Lawrence and Murphy, who had gone from doing standup to being movie stars, and then had embarrassing public episodes that called into question not only their fitness for the spotlight but also our culture’s ability to accommodate rare talent in black artists. The first episode of “30 Rock” features a quick montage of Tracy’s recent erratic behavior, including a clip of him walking through traffic in nothing but briefs, brandishing a toy lightsabre and screaming, “I am a Jedi!” It was an obvious echo of a 1996 incident in which Lawrence ran onto Ventura Boulevard, in Sherman Oaks, California, carrying a handgun in his pocket and shouting, “Fight the establishment!”

When critics pointed out the resemblance, Morgan worried that he might have offended his friend, and he went to Fey. “He was right to be concerned,” she told me. “When you come out of ‘S.N.L.,’ and you’re just used to doing whatever you want all the time, you’re just, like, ‘Yeah, listen, I think it’s gonna be fine.’ ” Lawrence had joked about the incident, too: on his widely praised standup special “Runteldat,” from 2002, he admitted that he was on drugs at the time. “I was smoking that ooh-wee! ” he says. “What kind of shit has the dope man sold me?!” Morgan went to Lawrence, who, he says, told him, “If it’s funny, do it.” It was Lawrence, Morgan added, who got him “to see that the court jester was the noblest person in the court. He was the only one allowed to tell the truth.”

Morgan has never had a problem with jokes that use his own persona as the punch line. During his first season on “S.N.L.,” he woke up one morning unable to see. He was given a diagnosis of diabetes, but he continued to eat and drink heavily. In 2004, after the cancellation of “The Tracy Morgan Show,” he went on the road to do standup, and the drinking worsened—twice, he almost slipped into a diabetic coma. He was arrested for drunk driving in December, 2005, and sentenced to three years’ probation; then, a month after the “30 Rock” première, in the fall of 2006, he got another D.U.I. During the show’s second season, he was using insulin whenever he felt sick. His immune system finally gave way, and he was admitted to the hospital with pneumonia. His doctors told him that he should have been dead. “We would be shooting, and between takes someone would come into his dressing room and take part of his foot off,” Fey said. He shot much of that season wearing a court-ordered ankle bracelet, on account of the drunk-driving convictions. “And, to his credit, he was, like, ‘Yeah, fine, write jokes about it,’ ” Fey said. She hadn’t planned for the character to share a first name with Morgan, but he had insisted. “ ‘I’m gonna get famous doing this,’ ” Fey remembers him saying. “ ‘I don’t want people yelling at me on the street going, like, “Hey Chickie!” ’ He wanted that Jerry Seinfeld mold of ‘Just call me Jerry if you see me on the street.’ ”

The role not only artfully transmuted Morgan’s persona but also used the unique unction of his performance to comment on the entanglement of race and comedy. The show’s eighth episode, “The Break-Up,” featured a secondary plot about the relationship between Tracy Jordan and a “T.G.S.” staff writer nicknamed Toofer—as in “twofer,” because he is, as one character puts it, both “a black guy” and “a Harvard guy.” Toofer, played by Keith Powell, is a parody of the kind of highly educated, quasi-intellectual black person who might view broad humor like Tracy’s—and Morgan’s—as embarrassing to the race. Tracy is cast in a “T.G.S.” skit as a woman named Shamanda, and Toofer objects. “I just think it’s demeaning for a black man to do drag,” he says, adding, “Chris Rock doesn’t do it. Dr. Cosby doesn’t do it.” Tracy decides he won’t do it, either; then the bit is a smash with a white castmate in the part. Tracy, regretful, angrily regales Toofer with a counter-canon: “Eddie does it, Martin does it—Jamie Foxx, Flip Wilson!” The exchange pinpoints a tension between divergent styles in black comedy—a divide that has to do not only with personal sensibility but with how much a given comic cares about how white people view his work. It calls to mind a routine from Murphy’s standup special “Raw,” in which he describes getting an out-of-the-blue phone call from Cosby, who, he says, demanded that Murphy refrain from all the “filth-flarn-filth” in his act.