A mechanic who did not want any of this, distrusts everything alien, and ends up running the agency.
Alphonso Mackenzie is a S.H.I.E.L.D. mechanic under Robert Gonzales, a founding member of the so-called real S.H.I.E.L.D., who infiltrates Coulson’s group with Morse. After being briefly mind-controlled by Kree technology his distrust of the alien and the superhuman deepens, and he leaves when his own leaders agree to work with the other side. Henry Simmons plays him.
He is the one character in that series who keeps saying the sensible thing out loud, which is why the show has to keep answering him.