His family came to California to grow fruit trees, but in 1916 he met photographer Alfred Stieglitz, who convinced him to devote his life to the then emerging world of artistic photography.

In 1922 Hagemeyer built a spring-summer studio in Carmel-by-the-Sea, California, at that time the largest art colony on the Pacific coast, and donated his photographs that December to a local fund-raising exhibit.

He moved his Carmel address in 1924 to a new "artfully designed studio" at the prominent junction of Mountain View and Ocean Avenues, which became a meeting place for intellectuals as well as a "gallery" to display the works of local and visiting artists.

[3][8] In February 1932 at the Haggin Museum in Stockton, California Hagemeyer displayed his photographs in a joint exhibition with Carmel's most famous Impressionist painter, William Frederic Ritschel.

[10][11] From the 1920s through the 1940s Hagemeyer photographed leading figures of the day, including Pedro Joseph de Lemos, Albert Einstein, and Salvador Dalí.