The correspondence between Thomas MacGreevy and George Yeats, some 150 extant letters, spanned 43 years, from 1922 through 1965. It was a relationship that began when Yeats was 30 and MacGreevy 29, and ended only with their deaths. George Yeats and Thomas MacGreevy probably first met at the United Arts Club in Dublin, where they soon discovered a shared love of gossip, the arts, and film. Her earliest surviving letter to him in 1922 is an invitation on Arts Club stationery to join her at the Corinthian cinema to see Charlie Chaplin; they had dined and gone to the 'Pictures' just a few days earlier. In his company as in few others she could relax, say what she thought, and joke, confident that she would be understood. Born only a year later (1893), in many ways MacGreevy was like a younger brother – she could scold, complain, contradict and confide in him, discuss music and books. For MacGreevy, George was a not simply a confidant, but an intelligent and sophisticated critic whose opinion he valued and respected. She supported him though his many life changes in the first decade of their friendship as he moved from Dublin to London to Paris.

He was also a strong support in her never-ending care of W.B. Yeats and her children, cheerfully and ably fulfilling innumerable errands ranging from having the telephone mended and measuring filing cabinets to checking on the children's welfare or keeping Willy occupied while she was away. When she became secretary of the Dublin Drama League Tom was drafted to act and produce occasionally, to translate, and to serve as a sounding board concerning contemporary European drama. In their later years when MacGreevy was extremely busy as Director of the National Gallery of Ireland, and Yeats was somewhat isolated living in the Dublin suburbs, he was a devoted friend, frequently asking her to tea at the Gresham Hotel and ably assisting with Jack B Yeats's care until the painter's death in 1957.

George Yeats was born in England yet through her marriage in 1917 she was catapulted into the centre of cultural and nationalist Ireland, George Yeats was always conscious of her foreign status. MacGreevy too felt himself to be an outsider in Dublin, having arrived only shortly before she did.note Born in Tarbert, Co. Kerry, MacGreevy had been a junior member of the civil service until the Great War; as second lieutenant in the Royal Field Artillery he fought at Ypres and the Somme, and was twice wounded. When he was demobilized he entered Trinity College as a mature student, taking an honours degree in political science and history. By June 1919 he had met both Lennox Robinson and Hester Travers Smith, and found a congenial base at the United Arts Club; Hester's daughter Dolly, who was to marry Lennox, remembered meeting him while he was still in uniform which he was required to wear until his demobilization in January 1919.

After graduation from Trinity, he was appointed assistant secretary to the Irish advisory committee of the Carnegie Trust, where Lennox was employed as an organizing librarian. But like Lennox his ambition lay in the arts. Unlike Lennox, however, while Tom was working at one thing, he was always restless to begin the next: literature, music, the ballet, and most of all painting consumed him. Later, when comparing himself to Samuel Beckett, with whom he taught in Paris, he confessed that he had 'always been as much interested in living as in writing about living.' Although he poetic output was not prodigious, Yeats, doubtless encouraged by George, spoke of him as 'the most promising of all our younger men.... I know from his criticism, his talk, how rich he is in imagination and in knowledge, and with proper encouragement he should be able to do again many times what he has done once.'

MacGreevy was a brilliant conversationalist, and George, like many in MacGreevy's life, valued his wit, his intelligence, and his breadth of knowledge on a wide variety of subjects. After the Yeatses settled permanently in Dublin in 1922 they soon became friendly enough for her to summon him to dinner at the Club, or tea and an adventure. MacGreevy's upbringing in Tarbert and his limited experience with outgoing, open-minded women, caused him to be more formal and correct than Yeats would have liked. But George was always good at breaking through the barriers of shyness and it was not long before she was one of his most trusted confidants and – most important – of his writing, which she encouraged, but did not hesitate to criticize. She was also tactful in deflecting what she felt were some of his more outrageous ideas.

When MacGreevy moved to London in 1925, George missed his regular presence in her life. 'I wish you were back here,' she wrote. 'Willy said last night very solemnly “Now McGreevy is not here we have to do our own gossiping” and there's nobody here now who has more than one idea in six months.' The friendship continued however, in lengthy letters and occasional meetings in London or Paris and later, Italy. Yet the empathy was not one way. MacGreevy's was a considerate correspondent, frequently asking after the children, admonishing George to take better care of herself, and sympathising with her about the difficulties she had balancing the demands of her children, her husband (who was like a third child at times), and her own creative outlets. When Willy was in London, she made certain that Tom knew his address. George's own visits to London were often rushed, especially when she was in charge of a Cuala sale, but she and Tom always managed to meet for at least dinner at Gennaro's and a film. And she introduced MacGreevy to many of her London friends.

When Dolly Travers Smith and Lennox finally married in 1931, Tom would become lonelier still. The marriage was particularly devastating for MacGreevy and he felt betrayed. For some years his relationship with George also cooled. Apart from occasional flying visits, it would not be until MacGreevy returned to live Ireland permanently in 1941 that they would pick up their old ties in the same close way. He was also a close friend of Jack Yeats, serving as executor to the painter's estate, and so had a special relationship within the larger Yeats family. MacGreevy enjoyed practising elaborate diplomacy, one of the reasons he liked to gossip, and in later years that diplomacy was a great help to George. During the complex negotiations between France and Ireland concerning the return of Yeats's body to Ireland, he served as George's liaison with the Irish government; he accompanied the family to Sligo on that occasion, and later was present when further formalities were exchanged with the Irish navy. In those later years the friendship was important to both of them, his care in providing social opportunities for her repaid in her concern for his health, such as sending him a hot water bottle for his aching shoulder, a remnant of a wound he received during the Great War. They met regularly for tea at the Gresham Hotel, and once again George could confide her concerns to him. He died in 1967, just one year before her own death.