|First appearance in comic||
Atlas May was the owner and operator of the Little Daisy Cafe in St. Louis.  In 1920 he established the Lackadaisy Speakeasy in limestone caves located under the Little Daisy Cafe. The speakeasy was a success, but in 1926 Atlas was killed violently, though the exact circumstances have not been revealed. The inheritance of Lackadaisy by Atlas's widow, Mitzi, and the subsequent decline of the speakeasy form the backdrop of the comic.
In the comic
"Arithmophobia" reveals that Mitzi keeps a portrait of Atlas in her office, and speaks to it on occasion. In "Rendezvous", Mitzi notes a picture of the former Lackadaisy crew, most notably Atlas, before she kisses Wick.
In "Portraiture", Mitzi again talks with the portrait of Atlas, noting that the guns used by the pig farmers were taken from Lackadaisy's storeroom, and that she will be confronting an "old friend" regarding a "wayward golden boy" of Atlas's. "Demurral" reveals the "old friend" to be Asa, while "Heartstrings" reveals the "golden boy" to be Mordecai, who according to Mitzi worked with Viktor for years. "Heartstrings" also reveals that Asa had made trade route agreements with Atlas. The agreements do not apply to Mitzi, and furthermore Asa is obeying the orders of his employer. Asa later states to Mitzi in "Loggerheads" that he warned Atlas that he was getting in over his head; this earns him a sharp look from Mordecai, who abruptly excuses himself. In "Hamstring", Mordecai asks Mitzi whether she believes that Asa warned Atlas; she replies that Asa probably just said that in order to intimidate her. While granting the possibility, Mordecai wonders whether there might be some truth to it; according to him Marigold has been concerned about something and dealing with it aggressively, though he does not know the root cause. Mitzi notes that, in any case, Asa could not know the circumstances surrounding Atlas's death unless Mordecai told Atlas something, but Mordecai states that he would not do such a thing. "Hamstring" includes a flashback of Mordecai with a gun in his hand standing opposite Mitzi, though it is unclear whether the gun is being passed from Mitzi to Mordecai or vice-versa or whether this is related to Atlas's death.
Wick confronts Mitzi about Atlas's death in "Veracity". She states that she played no part in it, and loved Atlas; she lets the mystery concerning it linger only because she does not like to talk about it, but offers to tell Wick about it in the future.
Atlas appears in a New Year's picture taken in Lackadaisy in 1926, shown in "New Year".
Atlas was born in St. Louis on January 3, 1884, and stood a little over 6' tall. Atlas was murdered in 1926, making him 42 years old when he died. Beyond business acumen Atlas was born with no advantages. At the time of his death, Lackadaisy was the city's most lucrative and most popular speakeasy. Zib notes in "Scapegoat" that Atlas had a talent for "collecting strays" and providing them with "solid ground".
According to Tracy, Atlas completed his primary education.
In regards to Atlas's background, Tracy noted-
He’s been deliberately left rather in the shadows - how the living characters remember him is the important thing - but I suppose it doesn’t hurt to say that his parents were unremarkable lower-middle class sorts, he had two brothers, no extensive education, a short military career and a strong distaste for toiling under someone else’s supervision following the war. He had also established in that arena that he had a sort of cool-headed, natural charisma of his own. Why did starting a speakeasy seem like a good idea? Because although alcohol had been largely outlawed, the demand for it was ever fervent, and he had himself a conveniently secret place in which to house and sell it.—Tracy, 
Atlas is depicted as a human in "Counterpart".
Atlas and Asa were friends. "Heartstrings" establishes that while Asa and Atlas were also business rivals, they cooperated with regards to trade routes for their alcohol. Said agreements do not apply to Mitzi. A picture in "Scrapbook" shows Atlas and Asa sitting together companionably. In "Loggerheads", Asa tells Mitzi that he warned Atlas that he was getting in over his head.
Atlas is Ivy's godfather. He was a friend of Ruby, Ivy's father, when they were in school, and Ruby later assisted Atlas in liquor trafficking. Their relationship was close enough for Ruby to consider Atlas a sort of elder brother. Atlas knew Ivy, but not especially well.
In "Veracity", Mitzi tells Wick that she loved Atlas and had no role in his death.
The first gift Atlas ever gave Mitzi was a pearl necklace that she is still wearing in "Vestige". She treasures it because he presented her with it just after she had performed the Mata Hari song, and she could not believe that someone like him was interested in her. The gift of the necklace made her feel like a lady. Zib was present when Atlas gave Mitzi the necklace, and in "Vestige" he compares it to a leash, and accidentally breaks it when Mitzi backs away from him while he is touching it.
Zib believes that Atlas knew Zib would never leave Lackadaisy unless Mitzi did.
When Mordecai began working for Lackadaisy, Atlas provided him with tailored clothing for the first time, and taught him the importance of presentation. Mordecai has dressed sharply ever since.
In the present, Mordecai appears to have an atypical degree of interest in matters relating to Atlas, though it is unclear whether this is due to Atlas being his former employer, or whether Mordecai has other motivations. In "Monomania", Mitzi accuses Mordecai of overanalyzing a situation solely because Atlas was mentioned. "Scrapbook" includes a picture of Mordecai and Asa together.
"Rendezvous" is the first episode to indicate Mordecai's previous allegiance; it is revealed that there is a picture in Little Daisy showing Mordecai, Atlas, Viktor and other individuals together in the cafe. In "Portraiture", while speaking to Atlas's portrait Mitzi refers to Mordecai as "that wayward golden boy of yours". "Heartstrings" confirms that prior to Atlas's death Mordecai worked for him, and Mordecai shoots Asa a look when Asa claims to have warned Atlas that he was getting in over his head. In "Hamstring", Mordecai asks Mitzi whether she believes that Asa in fact warned Atlas, though she does not believe Asa, Mordecai notes that Asa may have been telling the truth. Mordecai does have information regarding Atlas's death, though he claims that Mitzi is the only other person he has shared it with.
In "Briar-patch", Wick confesses to having been interested in Mitzi since she was married to Atlas. Mitzi replies that Wick is fortunate that Atlas did not have him shot, though it is not explicitly clear whether Atlas was aware of Wick's interest in his wife.