After Andrew Behrendt received his Ph.D. in history in 2016, he hoped to land a full-time job as a professor. But he has applied for tenure-track faculty jobs continuously with no luck.

So Dr. Behrendt, who is 34, teaches a wide variety of history classes as an adjunct professor at the University of Pittsburgh. The pay is generally $4,000 a course. Doing that alone would make it hard to make ends meet, he said, and he earns the bulk of his income as a staff member at the University Center for International Studies.

Dr. Behrendt, whose wife teaches at a charter school, said his lower salary made it hard to save for a house or start a family – especially since he is also struggling to pay off his student loan debt.

He has considered looking for work outside academia, perhaps in government or the nonprofit sector. But he loves teaching, and “I’ve spent the last 10 years of my life training to do something relatively specific,” he said. “Trying to rebrand is an exhausting thought.”