He was born in 1887 to a Norwegian father and a German Catholic mother in Socorro County, New Mexico, the son of Augustus Halvorson "Gus" Hilton (August 21, 1854 - January 19, 1919) and Mary Genevieve Laufersweiler (December 3, 1861 - August 26, 1947). His parents were married on February 12, 1885 in Fort Dodge, Iowa.

Conrad's siblings were Felice A. Hilton (December 6, 1885 - February 12, 1968); Eva C. Hilton (December 29, 1889 - 1979); Carl H. Hilton (born January 1892, died 1956); Julia Hilton (1895 - 1897); Rosemary J. Hilton (June 20, 1898 - November 27, 1995); August H. "Boy" Hilton (born in 1901, death date unknown); and Helen A. Hilton (January 30, 1906 - February 22, 2003).

His father, Gus, who was the son of Halvor Nilsen Hilton and Karoline Hansdatter "Kari" Holum, was born on the Hilton family farm near Kløfta in Ullensaker, Norway, where relatives still live, emigrated to the United States in 1870. Conrad's mother was born in Fort Dodge, Iowa, the daughter of a German-born Roman Catholic merchant, Conrad Laufersweiler.

Conrad Hilton was educated at the New Mexico Military Institute, at St. Michael's College (now the College of Santa Fe), and at the New Mexico School of Mines (now New Mexico Tech). In his early twenties, he was a representative in the first legislature of the newly-formed State of New Mexico.

Hilton built a store in San Antonio, New Mexico, but he later moved to Texas. He entered the hotel business by buying the Mobley Hotel in Cisco, Texas, in 1919. The first hotel he had built was the Dallas Hilton, which opened on August 2, 1925. He formed the Hilton Hotel Corporation in 1946. The company expanded into credit cards, car rentals, and other travel services.

Hilton had three wives, Mary Adelaide Barron (married 1925 - divorced 1934), actress Zsa Zsa Gabor (married 1942 - divorced 1946) and Mary Frances Kelly (married 1976 - his death in 1979).

He and Barron had three sons, Conrad Nicholson Hilton, Jr. (1926-1969); William Barron Hilton (born in 1927); and Eric Michael Hilton (born in 1932). He and Zsa Zsa Gabor had one daughter, Constance Francesca Hilton (born in 1947), who is the only child born to any of the famous Gabor sisters.

Conrad Hilton died on January 3, 1979, in Santa Monica, California at the age of ninety-one from natural causes. He is interred at Calvary Hills Cemetery, in Dallas, Texas.

His estate founded the Conrad N. Hilton Humanitarian Prize. He left a quarter a million to each of his surviving siblings and ten thousand to each of his nieces and nephews. Barron Hilton, contested the will and won in 1988. The net worth of Barron, and his descendants, then jumped to over $335,000,000 (USD).

Hilton's autobiography, Be My Guest, was published in 1957 by Prentice Hall.