He was born in London to Thomas Hood and Elizabeth Sands in the Poultry (Cheapside) above his father's bookshop. Hood's paternal family had been Scottish farmers from the village of Errol near Dundee. The Elder Hood was a partner in the business of Verner, Hood, and Sharp, and was a member of the Associated booksellers. Hood's son, Tom Hood, claimed that his grandfather had been the first to opened up the book trade with America and he had great success in new editions of old books.
"Next to being a citizen of the world," writes Thomas Hood in his Literary Reminiscences, "it must be the best thing to be born a citizen of the world's greatest city." On the death of her husband in 1811, Mrs Hood moved to Islington, where Thomas Hood had a schoolmaster who, appreciating his talents, "made him feel it impossible not to take an interest in learning while he seemed so interested in teaching." Under the care of this "decayed dominie", he earned a few guineas—his first literary fee—by revising for the press a new edition of Paul and Virginia.
Hood left his private school master at 14 years of age and was admitted soon after into the counting house of a friend of his family, where he "turned his stool into a Pegasus on three legs, every foot, of course, being a dactyl or a spondee."; However, the uncongenial profession affected his health, which was never strong,and he began to study engraving. The exact nature and course of his study is unclear and various sources tell different stories. Reid emphasizes his work under his maternal uncle Robert Sands. But no papers of apprenticeship exist and we also know from his letters that he studied with a Mr. Harris. Furthermore, Hood's daughter in her Memorials mentions her father's association with the Le Keux brothers who were successful engravers in the City. The labour of engraving was no better for his health than the counting house had been, and Hood was sent to his father's relations at Dundee, Scotland. Here he stayed in the house of his maternal aunt, Jean Keay, for some months and then, after a falling out with her he moved on to the boarding house of one of her friends, Mrs Butterworth where he lived for the rest of his time in Scotland. In Dundee, Hood made a number of close friends with whom he continue to correspond for many years, led a healthy outdoor life, and also became a large and indiscriminate reader. It was also during his time here that Hood began to seriously write poetry and had his first published work, a letter to the editor of the Dundee Advertiser.
He had married in May 1824, and Odes and Addresses—his first work—was written in conjunction with his brother-in-law J.H. Reynolds, a friend of John Keats. S. T. Coleridge wrote to Charles Lamb averring that the book must be his work. The Plea of the Midsummer Fairies (1827) and a dramatic romance, Lamia, published later, belong to this time. The Plea of the Midsummer Fairies was a volume of serious verse. But he was known as a humorist, and the public rejected this little book almost entirely.
Hood was particularly fond of practical jokes which he was said to have enjoyed perpetrating on members of his family. In the Memorials of Thomas Hood largely written by daughter, there is a story of Hood playing one such joke on his wife. He instructs Mrs. Hood to purchase some fish for the evening meal from the woman who regularly comes to the door selling her husband’s catch. But he warns her to watch for any plaice that “has any appearance of red or orange spots, as they are a sure sign of an advanced stage of decomposition.” Of course when the fish-seller comes Mrs. Hood refuses to purchase her plaice she exclaims “My good woman… I could not think of buying any plaice with those very unpleasant red spots!” Hood was much amused by the fish-sellers expression of amazement at complete ignorance of the appearance of plaice.
The series of the Comic Annual, dating from 1830, was a kind of publication at that time popular, which Hood undertook and continued, almost unassisted, for several years. Under that somewhat frivolous title he treated all the leading events of the day in caricature, without personal malice, and with an under-current of sympathy. The attention of the reader was distracted, by the incessant use of puns, of which Hood had written in his own vindication:
"However critics may take offence,
A double meaning has double sense."
He was probably aware of this danger. As he gained experience as a writer, his diction became simpler.