During the war the O'Malleys worked hard on farming their land at Burrishoole (Ernie O'Malley had tried to sign up for the Irish army but was rejected on medical grounds). However, they still craved artistic and intellectual stimulation, and Ernie O'Malley wrote to a friend in 1941 complaining about the lack of [high] culture in the west: 'Helen and I have to go there [Dublin] every now and then to meet people who speak our own language. Here, nobody is interested in creative work ... I have nobody to speak the language of books, literature, or criticism' (quoted in Richard English, p53). A year earlier O'Malley had written to a friend: 'You have to be very self-supporting to live in the Irish countryside, I mean intellectually self-supporting. There is no art, no library worth a small curse, no one who writes or paints near you: very few people who read' (Letter, summer 1940). O'Malley did, however, greatly appreciate the local culture and immersed himself in the task of collecting and chronicling traditional tales and folklore from the Clew Bay and Achill area.
It was about this time (early 1940s) that Ernie O'Malley developed friendships with the painter Jack Yeats and the poet Louis MacNeice. O'Malley was to champion the painting of Jack Yeats, producing exhibitions and purchasing many works himself (both Ernie and Helen O'Malley were keen collectors of art, with Ernie O'Malley purchasing works by, among others, Paul Henry). In 1945 O'Malley was instrumental in helping stage a Jack Yeats exhibition in Dublin (the Jack B. Yeats National Loan Exhibition), loaning his own paintings and even writing the introduction to the exhibition catalogue. On being introduced by Catherine Walston to John Rothenstein, director of London's Tate Gallery, O'Malley set up a meeting between Rothenstein and Jack Yeats in December 1945. O'Malley tried (unsuccessfully) to persuade Rothenstein to host an exhibition of Irish painters in England with a reciprocal exhibition of British painters to be shown in Ireland. Another Irish artist championed by Ernie O'Malley was Evie Hone, with O'Malley opening her exhibition of paintings, stained glass and drawings at Dublin's Dawson Gallery in 1945.
Despite the births of two more children (Etáin in 1940, Cormac in 1942), by the mid-1940s the O'Malley marriage was becoming strained and in 1946 Helen asked for a divorce. During this year Ernie O'Malley was spending his time between the Walston's residences in Cambridgeshire and London, Burrishoole, and Catherine Walston's cottage at Dooagh, Achill. In addition to pursuing his (unsuccessful) plans for reciprocal Irish and British art exhibitions, he continued to write both his memoirs and other works. In the summer of 1946, O'Malley had published an article on the Irish painter Louis le Brocquy in the English review, Horizon.
It has been commented that having played his part militarily in establishing an independent Ireland, much of Ernie O'Malley's later life can be seen as a prolonged attempt to establish an independent Irish culture to accompany the new political entity. As well as championing Irish artists such as Jack Yeats and Evie Hone, and his own work of collecting folk tales and rural stories from the Clew Bay and Achill area, Ernie O'Malley also contributed to a number of literary ventures. O'Malley became involved with the journal The Bell, the Irish periodical established in 1940 by Seán O'Faoláin and edited from 1946 until its demise in 1954 by O'Malley's friend and former IRA comrade Peadar O'Donnell. The Bell aimed to review and comment on the society and culture created in the wake of the Irish revolution, and O'Malley became its book editor in 1947. It was Ernie O'Malley's involvement with The Bell that prompted Catherine Walston to ask her new lover, Graham Greene, to use his literary connections in London to secure introductions for O'Malley.
Ernie O'Malley also participated in a number of Irish intellectual bodies including the Irish Academy of Letters and the Bibliographical Society of Ireland. The Academy aimed to promote creative literature in Ireland, and was created in 1932 with founder members WB Yeats and GB Shaw. Ernie O'Malley was also a member in 1945 of the Friends of the National Collections of Ireland, a society whose purpose was to secure artistic works and historic objects for Irish national or public collections.