Every weekday morning for 30 years, my father donned his work uniform — a crisp blue or white shirt, dark slacks and a tie. He then drove to an elementary school on the northwest side of Detroit to instruct classrooms of 30 or more third- and fourth-grade students in the basics of addition, subtraction, multiplication and division.

My father, Harold Shelton Jr., worked in the Detroit Public Schools, a system struggling in the wake of factory closings, declining population and increasing poverty rates when he arrived in 1973. He was one of a handful of male teachers at his school and often the only one of color, despite his employment in a district composed almost entirely of African American students.

His career spanned seven presidents, and his trademark 1970s Afro, already salt-and-pepper in his late 20s, had given way to a fully white, slightly thinning head of hair when he retired in the early 2000s. He continued to work part time in elementary and middle schools across Metro Detroit, and his presence as a black man remained an anomaly. Even now, when ethnic and racial minority students make up the majority of children in American public schools, black men are less than 2 percent of the teaching force, according to the U.S. Department of Education.

In the fall of 2015, there was one fewer among those ranks: My father died after a long battle with diabetes and end-stage renal failure. When I posted news of his death and his obituaries on my personal Facebook page, I received the usual “sorry for your loss” or “you’re in my prayers” messages, which provided a small bit of comfort in a time of grief.

But then one man, a former student now in his late 30s, paid tribute in an unusual way. He told me that he had entered my father’s name as the answer to a security question needed to set up his online bank account. The prompt: “What is the name of your favorite teacher?” His answer: “Mr. Shelton.” I kept scrolling, clicking on each notification as they came pouring in.

Former students wanted to share their stories about my dad and the way his mere presence had shaped their perceptions of themselves and their ability to succeed. Most came from his male students, now in or approaching middle age.

“He changed my life.”

“He was the reason I became an engineer.”

“He was the first black male teacher I ever saw in a classroom.”

“He was like a father figure to me and other young black boys who didn’t have one.”

I’m sure the students who adored my father later encountered other educators of varying backgrounds who made an impact on their lives. Great teachers tend to do this regardless of race, gender or creed — my favorite instructors in elementary school, high school and college happened to be white women. But when my father passed, the common theme of admiration and appreciation that emerged during his viewing and funeral struck me. Former students came by the dozens to pay their respects to a man they considered a second father or, in some cases, the father they never had.

They reminisced about the trips he organized for students to attend Saturday afternoon basketball games at the University of Detroit and the hot chocolate he made for the students on safety patrol after they completed their morning duties keeping classmates safe during frigid Michigan winters. No one had ever taken them to a sporting event, they said, before my father did.

For these young black boys, going to school and seeing a man who resembled them in a position of leadership, honor and respect made a powerful impression. Just by doing his job, my father became a role model. Education Secretary John B. King Jr., a former high school social studies teacher from an African American and Puerto Rican background , has emphasized the importance of recruiting and retaining teachers of color. So did former secretary Arne Duncan, who addressed the deficit with film director Spike Lee during a 2011 town-hall-style meeting at Morehouse College in Atlanta, an all-male, historically black institution.

But teacher recruitment and, more important, retention will remain challenges for school districts across the nation as male and female college students continue to pursue majors and career fields that offer higher salaries and, too often, higher levels of respect. Attracting and retaining men of color, already underrepresented in our nation’s institutions of higher education, might be even more difficult.

In its 2015 report on teacher diversity, the Albert Shanker Institute, a nonprofit endowed by the American Federation of Teachers, found that nonwhite teachers were being hired at a higher rate than their white counterparts but were less likely to stay in the profession. Black men, who are more likely to teach in high-poverty, high-needs areas, have cited a lack of institutional support and the demands of test-score-based evaluations among the reasons for their departure.

And in Detroit, where my father spent his entire career, public school teachers have endured one of the worst years in the history of a long-beleaguered district, turning to mass sickouts to draw attention to hazardous working and learning conditions and threats to suspend pay for lack of funds.

In the midst of the mess in Detroit, I think of the many children deprived of the opportunity to spend their days with someone like my dad. This Father’s Day, my family will continue to celebrate his memory and mourn his absence — not only from our lives but from the lives of the thousands of children who became part of our extended family when they stepped into his classroom and saw their faces in his.