Lapham is a human emblem of the new American industrial economy of the 1870s. A self-made millionaire in the paint business, he is now one of the richest men in Boston and is radiantly proud of the fact that he has earned every dollar. Having grown up poor and undereducated in Vermont, he still speaks in a rustic vernacular and has yet to understand the rationale behind the rules of high society, let alone assimilate them. A simple, practical man with a sense of duty, he even put aside his business to serve in the Civil War, in which he was seriously wounded and achieved the rank of colonel. He can be boastful and garrulous, but he is not arrogant or overbearing.

Lapham is dearly devoted to his wife Persis, who in turn has supported him through thick and thin, and his two daughters. Penelope, the older girl, is relatively plain but witty and sardonic and, at least in the first half of the novel, never seems to take anything seriously; her sister Irene is the more beautiful but vapid and superficial. Irene falls for Tom Corey, the young man who comes to work for her father as a foreign sales representative, but Tom and Penelope have a mutual attraction that, Penelope fears, could break Irene's heart. This romantic subplot allows Howells to contrast Tom's family, part of the old Boston aristocracy, with the even wealthier but socially crude Laphams with whose daughter Tom's mother has snobbish doubts about his possible union.

The novel has almost the air of Greek tragedy in that Lapham is a man of stature who has fatal flaws that threaten to destroy him. He is a teetotaller, and when he does take the liberty of trying some wine at a dinner party, he embarrasses himself and his family by talking too much. He abstains from gambling, but, instigated by his former business partner and current gadfly Milton Rogers, he gets into financial trouble when he stakes money on bad property and bad stocks. And, to compensate for a traumatic event in his past, he is charitable almost to a fault to a pretty girl whom he employs as a typist in his office.

The style of "The Rise of Silas Lapham" is a dramatic realism similar to that found in the novels of Howells's contemporaries Frank Norris and Theodore Dreiser; the structure is straightforward, and the dialogue cuts to the core in laying bare the characters' sentiments and unfolding the plot. It may fall short of being a "great" novel, but for its candid portrayal of a specimen of the nouveau riche, it can be considered a minor monument of nineteenth century American literature.