The central theme of the novel is the sexual jealousy of Louis Trevelyan who unjustly accuses his wife Emily of a liaison with a friend of her father's. As his suspicion deepens into madness, Trollope gives us a profound psychological study in which Louis' obsessive delirium is comparable to the tormented figure of Othello, tragically flawed by self-deception. Against the disintegration of the Trevelyans' marriage, a lively cast of characters explore the ideas of female emancipation and how to distinguish between obedience and subjection. Although himself no supporter of women's rights, in this novel some of Trollope's most spirited characters are single women.

Published in 1869, the same year as John Stuart Mills' The Subjection of Women and while the Divorce Act was a relative novelty, He Knew He Was Right was a timely novel, drawing a fine line between the obedience of women within marriage and their total possession by men.