Rawdon Crawley, younger son of Sir Pitt, has a commission in the Life Guards Green, bought for him by his indulgent aunt, Miss Crawley, when he has been asked to leave Cambridge. He stands six feet high, loves sports, gambling, and women. He detests his pious brother and his reprobate father but gets along well with young men. Thackeray describes him as a "heavy dragoon with strong desires and small brains, who had never controlled a passion in his life." But he is not too stupid to suspect that Mrs. Bute wants Rebecca ruined so that she cannot become Sir Pitt's third wife and inherit the Crawley money.
Rawdon's marriage and his love for Rebecca and little Rawdy, tame him. Rebecca's loyal slave, he does not see through her activities and explains to himself that she is made to shine in society. He gambles to make a living but regrets what he and Becky are doing to Raggles. He rises to magnificence when he makes himself Becky's watchdog and later when he confronts Lord Steyne and Rebecca. Although Rebecca has held Rawdon in contempt, she admires his authority in that difficult situation, and after she is alone, she wishes she had Rawdon again — "She thought about 'him' with great sadness, and perhaps longing — about his honest, stupid, constant kindness and fidelity: his never-ceasing obedience; his good humour; his bravery and courage."
Rawdon's marriage is one of the most nearly honest actions in his life. When he takes little Rawdy to school, he comes away "with a sadder, purer feeling in his heart than perhaps that poor battered fellow had ever known since he himself came out of the nursery." After being tamed by his affection for Rebecca and his bewilderment over her treatment of him, he would sit for hours in his brother's house:
very silent, and thinking and doing as little as possible. He was glad to be employed of an errand: to go and make inquiries about a horse or a servant: or to carve the roast mutton for the dinner of the children. He was beat and cowed into laziness and submission. Delilah had imprisoned him and cut his hair off, too. The bold and reckless young blood of ten years back was subjugated, and was turned into a torpid, submissive, middle-aged, stout gentleman.
Separated from wife and son, although sending money for both, Rawdon dies of yellow fever in Coventry Island.