Walden, the son of an Episcopalian clergyman, grew-up in various cities in the U.S. He moved to Paris as a young man and studied under Carolus Duran. He became a successful artist there, adept at both figural painting and in depicting seascapes. "The King of Bohemia", as he was known to his artistic circle, was a frequent contributor to the Paris Salons and received several awards and honors for his work. He also exhibited work in the Saint Louis Exposition of 1900 and the Panama-Pacific International Exposition in San Francisco in 1915.
His first visit to Hawaii was in 1911, at the invitation of a friend and fellow-artist, Kimo Wilder, whom he had met in Paris. So taken was he by the beauty and light of the Islands that he became a frequent visitor and an active participant in Hawaii's artistic life. He contributed to many group shows of Hawaiian artists and was for many years involved with the Hawaiian Society of Artists and the Honolulu Academy of Arts (formed in 1927).
Walden was considered the finest seascape painter of his time in Hawaii. Unlike many of his peers, he preferred to concentrate on the many moods, colors and movements of the ocean rather than in depicting the drama of volcanic eruptions and lush landscapes, although he did paint these themes on occasion as well.
While he is best known for his moonlit views of the Hawaiian coast, Walden's primary residence and first love was France. He died there in Chantilly in 1933.