|Portrayed by||Ming-Na Wen|
Agent May is an extremely intelligent woman who presents a stoic, rather uncommunicative demeanor at all times. According to Agent Coulson, earlier in her career May was a much friendlier person, prone to playing pranks on her fellow agents and generally happier, though still rather quiet. A tragic experience while on a mission in Bahrain to contact an unregistered gifted individual left May emotionally scarred and caused her to become the rigid, somewhat withdrawn person she is today. She is frequently the pragmatist to Coulson's more humanitarian approach, for example, in "Repairs" when she tranquilizes Hannah Hutchins to ensure the situation does not escalate. May is fiercely loyal to her S.H.I.E.L.D. team and will do whatever it takes to keep them safe. Sometimes her methods appear harsh but this is due to her dedication to protecting those in her charge.
May is a top-notch pilot, and remarkably skilled at martial arts. She was a resourceful and good field agent, earning the nickname "The Cavalry", apparently at least in part due to unspecified events in Bahrain ("0-8-4"). She was so talented at her job that she became a legend within the agency. Despite leaving the field a while ago, she still retains her licence and training to fly an airplane.
May used to be a field agent for S.H.I.E.L.D., and was highly skilled at her job. During her time as a field agent, she became somewhat of a legend at the agency. 
On a mission in Bahrain to make first contact with an unregistered gifted person, several of Agent May's colleagues and a young civilian girl were taken hostage by the man's followers. Agent May single-handedly stormed the building in which the hostages were being held and killed an unknown number of assailants, all while unarmed herself. She managed to free all of the hostages unharmed. However, the experiences May had on that mission, which she refused to fully disclose to Phil Coulson, left her emotionally scarred and caused a radical change in her personality. After this mission May attained almost legendary status within S.H.I.E.L.D. for her exploits, which earned her the nickname "The Cavalry." (Repairs)
In "Turn, Turn, Turn" May states that she put together the team, by essentially guiding Coulson to chose the people she would need, including the tech-bio combo of FitzSimmons and Ward as a specialist, if it became necessary to put Coulson down.
Grant Ward: Colleague and "friends" with benefits (the latter is not to be made public, as evidenced by the flat, angry glare she gives him at the start of "The Bridge", when, during a sparring session on The Bus, he alludes to it. He later speaks of the issue directly, saying he can 'separate Church from State'). She informed Coulson in "Seeds" of this, saying, "Agent Ward and I have been having sex . . .", and later confirming that he had heard her statement.
Jemma Simmons: Colleague
Skye: Colleague, not entirely trusted. Skye dredges up painful issues, and provokes unwanted questions, causing May to occasionally, perhaps unintentionally, use her to vent her own frustrations. May, however, seemed more than willing to beat Ian Quinn to death with her bare fists for shooting Skye.
- Melinda - "Gentle" 
- May - Likely to be 梅 in Mandarin Chinese, which means "plum" or "prune".
- Her current ID badge serial number is A 078624; the card was issued on 4 September 2013, and will expire on 4 September 2019.
- Melinda is helping Coulson figure out what happened to Skye's parents.
- Also known as The Cavalry.
The full May gallery can be found here.
"Girl in the Flower Dress"
Coulson: Go ahead, say it.
May: I don't do petty.
Coulson: But you called it. I trusted my gut even though you said she was a risk.
May: When someone breaks into my house, I usually don't invite them to stay. But that's me.
Coulson: That's me too. Then that alien staff went through my heart.
May: Sure it didn't go through the brain?
Coulson: You really don't do comforting either, do you?
Coulson: I can't think of a single time when anything alien in human hands ended well.
Skye: Wouldn't mind getting my human hands on Thor. He's so dreamy...
Coulson: Sure, he's handsome, but-
May: No. He's dreamy. [Walks on. The other two stare after her, somewhat surprised.]
Ward: Really? You think Coulson will take that excuse if he finds out about us?
May: He took it okay when I told him.
Ward: Wait? You told him?