After returning to the United States, she worked for approximately forty years as a nanny in Chicago, Illinois.
During those years, she took more than 100,000 photographs, primarily of people and cityscapes in Chicago, although she traveled and photographed worldwide.
Her photographs remained unknown and mostly undeveloped until they were discovered by a local Chicago historian and collector, John Maloof, in 2007.
Following Maier's death, her work began to receive critical acclaim. Her photographs have been exhibited in the U.S., Britain, Germany, Denmark, Norway and Belgium, and have appeared in newspapers and magazines in the U.S., Britain, Germany, Italy, France, and other countries.
