Founded in London in 1843 by Scottish brothers Daniel and Alexander MacMillan, the firm soon established itself as a leading publisher in Britain.

It published two of the best-known works of Victorian-era children's literature, Lewis Carroll's Alice's Adventures in Wonderland (1865) and Rudyard Kipling's The Jungle Book (1894).

[4][5] Former Prime Minister of the United Kingdom, Harold Macmillan, grandson of co-founder Daniel, was chairman of the company from 1964 until his death in December 1986.

[7] Other major writers published by Macmillan included W. B. Yeats, Rabindranath Tagore, Nirad C. Chaudhuri, Seán O'Casey, John Maynard Keynes, Charles Morgan, Hugh Walpole, Margaret Mitchell, C. P. Snow, Rumer Godden and Ram Sharan Sharma.

[9] After retiring from politics in 1964, former Prime Minister of the United Kingdom, Harold Macmillan, grandson of co-founder Daniel, became chairman of the company, serving until 1974 when he handed on the chairmanship to his son Maurice Macmillan[10](who in turn left the government, having been Paymaster General in the defeated government of Edward Heath) and took on the more honorific position of President[11] until his death in December 1986.

[17] According to The New York Times, Macmillan and other major publishers "fear that massive discounting [of e-books] by retailers including Amazon, Barnes & Noble and Sony could ultimately devalue what consumers are willing to pay for books."

[20] In December 2013, a federal judge approved a settlement of the antitrust claims, in which Macmillan and the other publishers paid into a fund that provided credits to customers who had overpaid for books due to the price-fixing.

[24] In 2012, parent company Holtzbrinck reorganized; Macmillan's consumer publishing operations were now led by John Turner Sargent from New York City.

[28] In January 2019, Toronto, Canada-based online writing community Wattpad announced an agreement with Macmillan [sic, Springer Nature America] for handling sales and distribution in the U.S. for its new publishing division Wattpad Books, alongside rival Penguin Random House that will handle the U.K. and India market, and Raincoast Books for the Canadian market.