Retired Army Gen. Mark Milley — the former chairman of the Joint Chiefs of Staff, who talked up constitutional values while serving under then-President Trump — is joining Georgetown and Princeton, his alma mater, to teach national security.

Why it matters: Milley, already a popular public speaker after leaving office in the fall, said he's looking forward to shaping "our national security leaders of the future."

Context: Milley, 65, who retired as the nation's highest-ranking military officer, told The Atlantic's Jeffrey Goldberg — in an extensive profile called "The Patriot" published in November— that he shouldn't have joined Trump in his famous walk to Lafayette Square during the racial-justice protests of 2020.

• "As a commissioned officer, I have a duty to ensure that the military stays out of politics," Milley said. "The political people, the president and others can do whatever they want. But I can't. I'm a soldier, and fundamental to this republic is for the military to stay out of politics."
• Milley said during his farewell remarks in September that military members "don't take an oath to a wannabe dictator. ... We take an oath to the Constitution."

Details: Milley joins Georgetown, beginning this semester, as a distinguished fellow in residence with the Security Studies Program in the School of Foreign Service.

• Georgetown said Milley will "mentor and engage with students, work closely with program faculty, and offer his insights in events with members of the broader Georgetown community."
• Joel Hellman, dean of the School of Foreign Service, said Milley's "lifetime commitment to service in the interest of our nation's security will surely inspire our students and enrich our community."

Milley earned his bachelor's in politics from Princeton in 1980, and received his commission from Army ROTC. He now joins the Princeton School of Public and International Affairs (SPIA) as a Charles and Marie Robertson visiting professor and visiting lecturer.

• The appointment begins this month and runs through June 2025.
• Princeton said Milley "will serve as a guest lecturer, meet with students, engage with alumni and faculty, and provide input on the School's Security Studies Ph.D. program," as well as participate in SPIA events in Washington.
• Amaney Jamal, the school's dean, said students will benefit from Milley's "experience in the nation's capital as well as abroad in conflict zones."

Fun fact: Milley played ice hockey for four years at Princeton.

• Milley is represented by Robert Barnett and Michael O'Connor of Williams & Connolly.

Go deeper: Milley bio ... Princeton announcement.