Painter and muralist Alphonse Emile Sondag was born in Paris, France but was raised in San Francisco, California from an early age. After finishing elementary school, he returned to Europe at the age of seventeen to study at the Ecole des Beaux-Arts. Earning a scholarship to study aborad, he then spent a year in Spain before returning to the U.S. in 1896. He enrolled at the Mark Hopkins Institute in San Francisco and in 1900 moved to Honolulu.

In the early 1900s he returned once more to California, building a home and studio in Fruitvale near the San Francisco Bay. With the onset of World War I he enlisted in Army and was sent to Europe, where he sketched the villages he saw in France and Belgium for future paintings. One the war ended, Sondag took up a position as staff artist for the National Parks Service while living in Kenwood, California. Among the works he executed for the department was a mural depicting the raising of the Bear Flag on Treasure Island in the San Francisco Bay; it was exhibited at the 1939 World's Fair on the island before being installed at the Sonoma Depot Museum. 

Sondag became an active member of the San Francisco art community. He was known for his imagery of California missions and Gold Country scene, and depictions of historic ships, as well as scenes of Honolulu and Europe.

He exhibited in the Oakland Art Gallery; the Golden Gate Exhibition (1939). His work can be found at the the State Rescource Center (Sacramento); the Oakland Museum; at Mission San Rafael; Mendocino County Museum; California State Library; Sonora Chamber of Commerce; and the Eureka, Ukiah, and San Rafael, CA courthouses.

Alphonse Emile Sondag died in Santa Rosa, California on February 3, 1971.