When I was fifteen, my journalism teacher told me I was talented enough to someday be editor of the school’s newspaper. He told me I was a gifted writer and a solid journalist, with the potential to be an exceptional leader. With those words, he helped write the plot of one of my life’s major storylines.

He saw these traits in me before I even had an inkling they existed.

That teacher, Thomas Toulmin, died this month, and I’ve been reflecting since about his role in my life, in the career paths I’ve chosen, in the vision I’ve built of myself—one he helped create.

Fun fact: in my original version of the previous sentence, I’d written “passed away” instead of “died.” But the Mr. Toulmin who taught me so much of what I know about journalism would have taken a red pen to that phrase. “Euphemism,” he would have written. “Be precise.”

His devotion to the concept of telling it like it is, his commitment to details and facts, once led to a huge blow up between us when I was a senior in high school and editor of The Lion’s Tale. He told me point blank that the paper was going to run a story about an important incident at the school involving a close friend of mine. I didn’t think we should cover it. Privacy, I insisted. We’d be like vultures feeding off someone’s misfortune.

Though he expressed deep empathy, Mr. Toulmin didn’t waver in his stance. “People will just spread gossip if we don’t print the facts,” he said (and of course I’m paraphrasing). “It’s a journalist’s job to get the truth in front of the public. It’s our ethical obligation.” I continued to balk, and he finally said, “I understand your concerns. You don’t have to be the one to write it, but it’s going in the paper.”

Mad as I was, I wrote the story myself and, in the process, learned a huge lesson—doing what’s easy isn’t always right, and doing what’s right isn’t always easy.

I also learned that you can treat people with kindness and compassion and still have expectations of them. I learned how to be a caring leader.

Over the years, Mr. Toulmin turned into Tom. We became colleagues, and then friends. I’m glad that over the course of that time, I was able to express what his influence meant to me.

I know I’m not the only one of his former students grieving. Hundreds of us—his sloths and later, I’m told, his vegetables—can tell similar stories of his impact on our lives. For all of us, the loss of his physical being leaves a void. But within that void, the steady light of his legacy continues to burn.