It's not just Trump's pick for his administration. The current Defense Secretary (Lloyd Austin) is a 40 year Military veteran, and the two in Trump's previous term (Esper & Mattis) both served in Iraq and saw combat.
There's a much stronger tradition of military leadership going into politics in the US than the UK - and it's widely viewed as a very positive thing, and not just by the nutty rednecks in flyover states.....my wife is a tree-hugging liberal, but she worked with folks from the US military in previous jobs and has a ton of respect for them as a staggeringly competent organization.
Maybe something the UK could copy? A lot of government departments are basically just massive exercises in logistics, which is exactly what the military does best.