In December 1905, after returning to Washington from their diplomatic travels, Alice became engaged to Nicholas Longworth III, a Republican U.S. House of Representatives member from Cincinnati, Ohio, who ultimately would rise to become Speaker of the House.
The two had traveled in the same social circles for several years, but their relationship solidified during the Imperial Cruise.
A scion of a socially prominent Ohio family, Longworth was 14 years her senior and had a reputation as a Washington D.C. playboy.
Their wedding took place in February 1906 and was the social event of the season.
It was attended by more than a thousand guests with many thousands gathered outside hoping for a glimpse of the bride.
She wore a blue wedding dress and dramatically cut the wedding cake with a sword (borrowed from a military aide attending the reception).
Immediately after the wedding, the couple left for a honeymoon that included a voyage to Cuba and a visit to the Longworths in Cincinnati.
This was followed by travels to England and the Continent which included having dinners with King Edward, Kaiser Wilhelm, Clemenceau, Whitelaw Reid, Lord Curzon, and William Jennings Bryan.
They bought a house at 2009 Massachusetts Avenue, N.W., in Washington, D.C., now the headquarters of the Washington Legal Foundation.

Alice publicly supported her father's 1912 Bull Moose presidential candidacy, while her husband stayed loyal to his mentor, President Taft.
During that election cycle, she appeared on stage with her father's vice presidential candidate, Hiram Johnson, in Longworth's own district.
Longworth later lost by about 105 votes and she joked that she was worth at least 100 votes (meaning she was the reason he lost).
However, he was elected again in 1914 and stayed in the House for the rest of his life.

Alice's campaign against her husband caused a permanent chill in their marriage.
During their marriage, she carried on numerous affairs.
As reported in Carol Felsenthal's biography of Alice, and in Betty Boyd Caroli's The Roosevelt Women, as well as by Time journalist Rebecca Winters Keegan, it was generally accepted knowledge in D.C. that she also had a long, ongoing affair with Senator William Borah, and the opening of Alice's diaries to historical researchers indicates that Borah was the father of her daughter, Paulina Longworth (1925–1957).

Alice was renowned for her "brilliantly malicious" humor, even in this sensitive situation, since she had originally wanted to name her daughter "Deborah," as in "de Borah."
And according to one family friend, "everybody called her [Paulina] 'Aurora Borah Alice.'"

On May 11, 1908, Alice similarly amused herself in the Capitol's gallery at the House of Representatives by placing a tack on the chair of an unknown but "middle-aged" and "dignified" gentleman.
Upon encountering the tack, "like the burst of a bubble on the fountain, like the bolt from the blue, like the ball from the cannon," the unfortunate fellow leapt up in pain and surprise while she looked away.
In December 1905, after returning to Washington from their diplomatic travels, Alice became engaged to Nicholas Longworth III, a Republican U.S. House of Representatives member from Cincinnati, Ohio, who ultimately would rise to become Speaker of the House. The two had traveled in the same social circles for several years, but their relationship solidified during the Imperial Cruise. A scion of a socially prominent Ohio family, Longworth was 14 years her senior and had a reputation as a Washington D.C. playboy. Their wedding took place in February 1906 and was the social event of the season. It was attended by more than a thousand guests with many thousands gathered outside hoping for a glimpse of the bride. She wore a blue wedding dress and dramatically cut the wedding cake with a sword (borrowed from a military aide attending the reception). Immediately after the wedding, the couple left for a honeymoon that included a voyage to Cuba and a visit to the Longworths in Cincinnati. This was followed by travels to England and the Continent which included having dinners with King Edward, Kaiser Wilhelm, Clemenceau, Whitelaw Reid, Lord Curzon, and William Jennings Bryan. They bought a house at 2009 Massachusetts Avenue, N.W., in Washington, D.C., now the headquarters of the Washington Legal Foundation.
Alice publicly supported her father's 1912 Bull Moose presidential candidacy, while her husband stayed loyal to his mentor, President Taft. During that election cycle, she appeared on stage with her father's vice presidential candidate, Hiram Johnson, in Longworth's own district. Longworth later lost by about 105 votes and she joked that she was worth at least 100 votes (meaning she was the reason he lost). However, he was elected again in 1914 and stayed in the House for the rest of his life.
Alice's campaign against her husband caused a permanent chill in their marriage. During their marriage, she carried on numerous affairs. As reported in Carol Felsenthal's biography of Alice, and in Betty Boyd Caroli's The Roosevelt Women, as well as by Time journalist Rebecca Winters Keegan, it was generally accepted knowledge in D.C. that she also had a long, ongoing affair with Senator William Borah, and the opening of Alice's diaries to historical researchers indicates that Borah was the father of her daughter, Paulina Longworth (1925–1957).
Alice was renowned for her "brilliantly malicious" humor, even in this sensitive situation, since she had originally wanted to name her daughter "Deborah," as in "de Borah." And according to one family friend, "everybody called her [Paulina] 'Aurora Borah Alice.'"
On May 11, 1908, Alice similarly amused herself in the Capitol's gallery at the House of Representatives by placing a tack on the chair of an unknown but "middle-aged" and "dignified" gentleman. Upon encountering the tack, "like the burst of a bubble on the fountain, like the bolt from the blue, like the ball from the cannon," the unfortunate fellow leapt up in pain and surprise while she looked away.
Alice Roosevelt Longworth