Herbert Hoover met Lou Henry during his senior year at Stanford. She also received a degree in geology. The daughter of a banker, her family moved from Iowa to California when she was ten years old. Hoover and Lou Henry got married on February 10, 1899, and left the next day for China where Hoover had been hired as a mining engineer. Together, they had two sons: Herbert Hoover Jr. and Allan Hoover.

Lou and Herbert Hoover learned to speak Mandarin Chinese while they were in China. Lou even created her own English-Chinese dictionary. It was said that the two of them would sometimes speak in Chinese when they did not want to be overheard.

Lou Hoover was very involved in the Girl Scouts, even serving as the organization's president at one point. She was a well respected first lady. As first lady she spent time restoring rooms in the White House. When the country was in its deepest depression, the Hoovers used their own money to pay for entertaining.