In 1911, at St. Thomas Episcopal Church, Washington, DC, she married Baltimore businessman Walter Booth Brooks Jr., in a ceremony called "one of the most brilliant social affairs in the Capital that season.

Walter Borneman describes Brooks at this time as “recently divorced, the mother of two young children, fabulously wealthy, and by all accounts the epitome of a liberated Roaring Twenties woman racing a breakneck speed to embrace far more rights than those granted by the recently ratified Nineteenth Amendment.” The pair announced their engagement in mid-January 1922 and were married on Valentine’s Day, at Louise’s stepfather’s Palm Beach villa.

[7] In January 1925, MacArthur was promoted, becoming the youngest major general in the U.S. Army; he and his wife returned to America, choosing to live at Louise’s estate, near Baltimore (and Washington, D.C.).

This time, with his marriage deteriorating, the general travelled alone; Louise had moved out of the estate with her children, adopting as her residence the entire twenty-sixth floor of the Beverly Hotel[8] in Manhattan.

[7] MacArthur gave the marriage only one sentence in his memoirs; "In February 1922 I entered into matrimony, but it was not successful, and ended in divorce years later for mutual incompatibility.