Stuyvesant High School is top-notch, übercompetitive. Prove the transitive postulate. Diagram xylem and phloem. Explain: Who was Robespierre?

But in Frank McCourt’s creative-writing class back in 1981, we sing bawdy folk songs, craft poetry from recipes, and pen courtroom dramas defending household objects. Our teacher is this generous renegade, a raconteur and wit also who succeeds in getting us to read Beowulf. Every Friday is “open mike,” when students can read aloud anything we’ve written: essays, poems, dramatic pieces. Because there’s nothing to memorize or regurgitate—and because Mr. McCourt doesn’t spoon-feed us facts—a few kids think creative writing is a goof-off class.

Not me. I’ve dreamt of being a writer since I was 8, and under his tutelage, I blossom. The free-range creativity is an enormous relief, a jolt of adrenaline. For 45 minutes, I get to aerate my brain, turn the world upside down, revel in music, poetry, humor. Creative writing in Room 205 hones my literary skills like a lathe. I begin writing and reading voraciously: Dorothy Parker. Langston Hughes. Truman Capote. “Samuel Johnson!” Mr. McCourt orders. “Jonathan Swift.”

I become his acolyte, a huge groupie. I’m too cool to moon around his desk after class, so instead I write something every single week for the “open mike,” hoping to impress him. To my great relief, the work I submit comes back with stellar grades and words of encouragement.

Since I’m a teenager, even my hair is an opera. The voices in my head are merciless: I’m fat, I’m unpopular, nobody likes me. Why can’t I look like the girls in the magazines? And my home life, I’m convinced, is hideous. After school, it’s nothing but screaming and slamming doors and “In my house you live under my rules!” I spend a lot of time crying in the stairwell and scrambling to finish my homework on parked cars outside of school in the morning. I call my father from a payphone during lunch, sobbing. One friend gives me Percocet he stole from his mom, another Black Beauties. At nightclubs, plenty of men give me coke. It would be so easy to just to sink into a well of medication.

But instead, I focus on Mr. McCourt’s class. “Oh, Miss Gilman,” he tells me. “You’ve got a gift.”

I write a series of vignettes about teenagers in New York City. “Take this piece of yours and send it to The Village Voice,” he urges.

I do. And the week before my 17th birthday, The Village Voice publishes my article, “Scenes from Stuyvesant High.” It’s the first time I’ve ever published professionally. Without telling me, Mr. McCourt submits my poetry to various contests—hosted by City College, by the National Merit Program. I win prizes. He has no idea how he’s saving my life, redeeming me from the abyss.

When I head off to college, he writes at length in my yearbook. His words to me are greater than any love poem: “Don’t, don’t, don’t ever let them still your voice…Go to your room and let your pen rip across the page…move over, Jane Austen. Bow your head, Mary McCarthy. Run for cover, Fran Leibowitz.” And in the darkest nights, when I’m ravaged with insecurity and despair, I re-read it. And I continue to write.

And we stay in touch. We get together for drinks when I’m in the city; I go back to Stuyvesant to visit. When I begin working as a journalist, Mr. McCourt becomes “Frank,” evolving into my mentor and friend. Whenever I have a professional triumph—an Op-Ed in The New York Times or a journalism award—I call him. He is as proud as any parent.

Yet in my heart, it doesn’t seem right. He is the major talent. He has so much wit and eloquence and gloriousness in him: I can’t help but feel that he was meant for better.

When I receive an advanced copy of Angela’s Ashes, I forsake all work, the boyfriend, the dishes. I cannot sleep. I thought I knew Frank well—but this? This is a masterpiece. It’s fireworks exploding. It’s symphonic. As soon as I put it down, I call him.

“Oh, I was hoping you’d like it,” he says, his voice full of astonishment.

* * *

We all know what comes next. The whole world gets to participate in Frank McCourt’s happy second act, in his global, spectacular success. We get to see what comes after the miserable Irish Catholic childhood, with its shiftless, loquacious alcoholic father, the pious defeated mother moaning by the fire.

All of us from Stuyvesant are practically dancing around on the phone to each other, we’re so gleeful and excited: He did it! He did it! The triumph, the justice of it, is monumental. The day he wins the Pulitzer Prize, I call him again, exultant.

“Oh, yeah, I’m a real big shot now, aren’t I?” he teases. “My agent called me this morning. Everyone’s calling me. It’s a little unreal. I can hardly believe it. It’s such good news, that I keep waiting, you know, for the other shoe to drop.”

“Oh, Frank,” I say softly. “Look at your childhood. Look at everything you’ve gone through. This is the other shoe, Frank.”

* * *

I myself become a published author. In 2005, when my second book, a memoir called Hypocrite in a Pouffy White Dress, debuts on The New York Times bestseller list, the first person I telephone is Frank. He isn’t home, so I leave a message on his machine. “Mr. McCourt,” I began, “it’s Susan Gilman, from your class in Room 205…” And then I began to cry.

Moments later, when he calls me back and says, “Is this The New York Times bestselling author Susan Jane Gilman?” I start sobbing all over again. “Oh, Mr. McCourt—”

Of course, I haven’t called him “Mr. McCourt” in decades. But for this call—this breathtaking, fantastical call—it’s Mr. McCourt I’m paying homage to, the selfless, inspiring teacher who is ultimately responsible for my becoming a writer, for my living a life full of humor and literature instead of drugs and despondency. “Mr. McCourt, I couldn’t have done it without you,” I choke into the phone. “You made me what I am today.” Oh, what clichéd lines! Oh, how he would—should—cross them out with a red pen and scribble in the margins: You can do better!

But instead, he chuckles. “I did, didn’t I?” he teases.

“You certainly did,” I say.