Born in Brooklyn, New York City on 19 August 1930, Frank McCourt is the eldest son of Malachy and Angela McCourt. He is joined by brother Malachy in 1931, twins Oliver and Eugene in 1932, and a sister, Margaret, in 1933. After the death of his sister Margaret when she was only a few weeks old, his family moves back to Ireland, where his younger twin brothers both die within a year of the family's arrival and where Frank's youngest brothers, Michael (b. 1936) and Alphie (b. 1940) are born.
Life in Ireland, and specifically life in Limerick City, in the 1930s and 1940s is described in all its grittiness. The family lives in a dilapidated lane of houses that regularly floods, and share one outdoor toilet or lavatory with all their neighbours. Although his father teaches the children Irish stories and songs, he is an alcoholic and seldom finds work (when he does he spends the paycheck money in the bars), and so they live on the dole (welfare) or charity while the father spends days drinking in bars. For years the family subsists mostly on bread and tea.
Frank's father finally gains employment during World War II at a defence plant in Coventry, England. In this situation, he finds it easy to drink away most of his wages, and only once does he send any money back to the struggling family in Ireland. Their mother is destitute, as there are not many jobs for women at the time, and must beg for help from the Church and the Society of Saint Vincent de Paul. Sometimes Frank and his brothers have to scavenge for lumps of coal or peat turf for fuel, or steal bread to survive. Angela's sister and her widowed mother begrudge any help they have to give her, because they disapprove of her husband, mostly because he hails from Northern Ireland and therefore he has a strange accent and what Angela's family calls 'the odd manner.' The McCourt family are continually afraid of going to hell if they do not pray or confess often enough as specified by the church.
In the damp, cold climate of Ireland, the children have only one set of ragged clothing each, patched shoes and no coats or boots. Frank develops typhoid and is hospitalized. Later, he gets a job helping a neighbor with leg problems deliver coal and develops chronic conjunctivitis. The family is finally evicted after Frank takes a hatchet to the beams to burn for winter heat and the ceiling collapses in on them. The family is forced to move in with a distant relative who treats them poorly, eventually having an affair with Frank's mother, Angela.
Teenage Frank starts work for the Post Office as a telegram delivery boy, and later delivers newspapers and magazines for Eason's. He also works for the local money lender writing threatening letters to the people who owed her money, as a means to save money and is finally able to realize his dream of returning to the United States. The story ends as he sails into Poughkeepsie, New York, to begin a new life at the age of nineteen.