Alphonso MacKenzie is the Director of S.H.I.E.L.D., a steady hand who bears the weight of command without letting it rattle him. After Daisy brings the synthetic recreation of their fallen friend online, Mack pulls rank, reminding the team that reviving an LMD is the Director's call to make. It stays running in the end, because the mission cannot succeed without his deep knowledge of S.H.I.E.L.D.'s history.

In 1931 he works the speakeasy alongside Coulson, posing as a bootlegger to reach the contact whose bar will one day become a S.H.I.E.L.D. safehouse, enduring the casual indignities a Black man faces in the era, brushed off as the white man's shadow, while keeping his focus on the mission. When the backroom turns hostile, Coulson draws the enemy's fire and discovers he can take it, while Mack drops the armed men around them. The cover carries the two of them deeper into the night's grand political gathering, where the hunt for the enemy's true target tightens around them.

Out in the field with Deke, Mack leads the run to move Freddy and the cargo the young man insists is nothing more than high-grade liquor. He does not buy it, knowing full well that no one sends killers after a man over a few bottles of hooch, and his digging turns up the truth Freddy tried to hide, a vial of green serum tucked inside a bottle of booze.

When the order comes down the radio to put a bullet in the boy, it is Mack who slams the door on it. He reminds Deke that the orders run through the Director and no one else, refusing to murder a kid to reshape a future he is sworn to leave intact, and talks him down from the shot. The reprieve lasts only until the hunters open fire, and Mack throws himself into the brawl, wrestling a weapon from one of them and dropping another, before the boy slips loose in the confusion and he sends Koenig and Enoch to run him down.