1880
Carnegie begins courting Louise Whitfield.
Although Carnegie is seeing several young women, he is most fond of Louise, and calls her his favorite riding partner. They become increasingly close.

1881
Carnegie acquires interest in Frick's company.
Carnegie, who has been one of Frick's largest coke customers, proposes a merger with Frick. At first Carnegie's interest totaled only about 11% of the stock, but he soon increases his share to over 50% of the company.

1881
Carnegie escorts mother to Dunfermline.
Carnegie invites Louise Whitfield to accompany him on his trip to Scotland, but his jealous mother intercedes, and Louise remains at home. Alone with her Andrew, Margaret travels to Dunfermline and parades in a coach in front of the townspeople. Andrew donates a library to the town, his first outside of the United States.

1883
Carnegie buys the Homestead Works, a rival mill.

1886
Carnegie defends unions.
In Forum Magazine, Carnegie publishes an essay defending workers' right to organize into a union. He also publishes Triumphant Democracy, which sells over 70,000 copies and celebrates the American belief in democracy and capitalism.

1886
Carnegie's mother and brother die.
At his home in Cresson, Pennsylvania, Andrew catches typhoid. He suffers a relapse when he learns of his brother's death. A month later, while Carnegie is still ill, his mother dies of pneumonia. In order to keep Margaret Carnegie's death a secret from her son, her coffin is lowered out of her bedroom window.

1887
Carnegie marries Louise Whitfield.

Carnegie and Frick disagree over a striking union.
Henry Clay Frick organizes a coalition of coke companies to resist striking labor, but Carnegie has a large enough share in Frick's company to force him to settle with the workers. The tension between the two men is resolved for the time being, but Carnegie and Frick will disagree on labor issues in the future.

1889
Carnegie publishes "The Gospel of Wealth"
Carnegie publishes "The Gospel of Wealth," arguing that the wealthy have a moral obligation to serve as stewards for society. By the next year, Carnegie's annual take-home pay is $25 million.