Cabinet heads are political appointees.
“Mr. McAleenan has been a member of the U.S. Government’s Senior Executive Service since 2006. Prior to government service, Mr. McAleenan practiced law in California. He received his Juris Doctor degree from the University of Chicago Law School and a Bachelor of Arts degree from Amherst College.”
According to this he is.
https://www.cbp.gov/about/leadership-organization/commissioner
Do appointees have to come from the SES? I heard it was rigged and one of the ways the deep state can surpass the will of the people with their trained ‘resistance operators’ lined up and ready to go.