When Skye, Melinda May, Antoine Triplett, Idaho, Lance Hunter, and Isabelle Hartley returned from unsuccessfully attempting to get a level ten file about an 0-8-4, Alphonso Mackenzie stopped watching a Glenn Talbot interview to greet them. Triplett explained to him that the mission did not go as planned and they didn't get anything new.
Later, Director Coulson explained to him and Billy Koenig that he sent the six into a government storage facility that housed S.H.I.E.L.D. paraphernalia despite the odds of success because they needed a Quinjet's cloaking technology to travel secretly. Coulson beleived that in Fitz's state he was incapable of completing the job of making the Bus undetectable. 
When Skye and Antoine Triplett returned to the Playground with a Quinjet, Mack was tasked with reverse engineering its cloaking technology for the Bus. He went to Leo Fitz for advice. During their interaction, he noticed that Fitz wanted to help against Carl Creel. Eventually, Mack learned to understand what Fitz was trying to say and helped Fitz to modify the Overkill Device which allowed Phil Coulson to subdue the Absorbing Man. This resulted in the forming of a friendship between the two, much to pleasure of the rest of the team, who were happy that Fitz was opening up to somebody.
The Moroccan MissionEdit
When Coulson returned from his debriefing with Jemma Simmons, he had a meeting with his agents, including Fitz and Mackenzie. When Fitz was asked for input on Donnie Gill, Mackenzie helped to translate Fitz's thoughts.
Gill froze the Maribel del Mar in a harbor in Casablanca, alerting both S.H.I.E.L.D. and HYDRA to his location. As the field agents left, Mack told Fitz that they could play Xbox. Fitz was upset because he wanted to go as well; Mack tried to make him feel better. After Fitz interrogated Grant Ward, he unplugged Mack's game and told Mack to contact the field agents about Gill's brainwashing.
Bonding with OthersEdit
Mack was the driver of a 1962 Rolls Royce that Phil Coulson and Melinda May used to get to a gala held to rebuild Santa Maria de las Flores. He told Coulson that he would wait patiently for him to give him permission to repair Lola. After they exited, Mackenzie went to South Beach to get Lance Hunter to take him to the Bus.
At the Bus, Mackenzie was bored with the stories Hunter told of his ex-wife and read a magazine.
Agent 33, disguised as Melinda May, put a virus in the electrical system of the plane that, if left unchecked, would cause it to explode. Mack acted as Fitz's translator to convey his thoughts on what was happening. Hunter and Fitz ultimately stopped the virus.
- S.H.I.E.L.D. (Second Incarnation) - Allies
- Agents of S.H.I.E.L.D.
- In the comics, Alphonso Mackenzie is a veteran S.H.I.E.L.D. agent and former CIA liasion to S.H.I.E.L.D.
- Mack likes singing in the shower.