Gorman was a sergeant in the Irish Guards, had quite a good record, and was awarded a medal in Burma. He was given a job at Bertram's Hotel, as a replacement for Parfitt, who had been in a car accident.
While Bess Sedgwick was staying at Bertram's Hotel, she recognised Gorman, and opened the window of the writing room to talk to him. She remarked that he drank too much, and always had. She also said that the army suited him, because he had always had courage and been a good fighter.
Gorman enjoyed gambling, and liked working at Bertram's Hotel because guests would sometimes give him good tips for Ascot and Newbury.
It is revealed that Gorman had been in a relationship with Bess when she was young. He told her that he had not forgotten Ballygowlan, and had sometimes thought of writing to her. She told him that in Ballygowlan, he was paid to keep his mouth shut, and he would not get any more money from her. He said that he was only joking, and would never do anything to hurt her.
Gorman felt that it was his duty as commissionaire to look after the ladies who stay at the hotel. He firmly advised Miss Marple against taking a bus, saying that it is dangerous to take a bus when one is getting older. He got a taxi for her by clicking his thumb, telling her that she would go wherever she wants to like a queen. On another occasion, he advised a middle-aged lady not to go out in the fog unless she had to.
Gorman was shot outside Bertram's Hotel on a foggy evening. He had heard a shot and a woman screaming, and had run down the street to investigate. A second shot was then heard, and he fell down, dead.
Elvira Blake told Chief Inspector Davy that someone had shot at her, and that Gorman had saved her life by pushing her back and getting in front of her. However, it was later revealed that Elvira was the one who had shot Gorman. She had fired a shot and screamed, and when he came running down the street, she shot him at close range.
It was further revealed that Gorman had been married to Bess Sedgwick, and that they had never been divorced. The reason they didn't divorce was that back then he had convinced Bess that their marriage ceremony had been a con. Perhaps he feared that Bess' family wouldn't pay him to give up Bess, if they learn of the marriage, or he worried about having broken the law by marrying a minor (Bess was sixteen at the time). Whatever the reason he didn't want the marriage to be known at the time. This meant that Bess' marriage to Lord Coniston was not legal. Elvira had thought that this meant she could not inherit Lord Coniston's money, so she killed Gorman to prevent him from telling anyone that he was married to Bess.
BBC's Miss Marple
In the BBC 1987 adaptation of the novel, Mickey Gorman is portrayed by Brian McGrath. This portrayal is fairly close to that in the original novel.
In the ITV 2007 adaptation of the novel, Mickey Gorman is portrayed by Vincent Regan. This portrayal is slightly different. Although Gorman and Bess Sedgwick had not seen each other for a long time, they still seemed pleased to meet again. In this adaptation, Gorman is also an amateur artist and painted many pictures with the figure of a woman with her back turned, always a little out of reach. Miss Marple interpreted this as an expression of love for someone unattainable. Another painting was a portrait with a distorted "modernist" face but wearing a necklace which Miss Marple recognised as that worn by Bess Sedgwick. Bess also admitted to Miss Marple that she still loved him and during the denouement, she affirmed that Mickey would not have blackmailed her or done anything to cause her harm. However Mickey had a drinking partner Tilly Rice and, some time earlier, while drunk, he had told Tilly something about his relationship with Bess Sedgwick. Tilly used this to blackmail Elvira Blake, causing Elvira to take the drastic steps she took to protect her inheritance.