Ten years later, following the death of his father, his mother moved the family to the Wilmar – South San Gabriel area, a then semi-rural suburb a few miles east of Los Angeles.
It was largely through his efforts that the young watercolorists of the California School were able to dominate the Society and establish it as an internationally recognized organization.
Gramatky was also among those whose work was exhibited in a major show of California artists mounted at the Art Institute of Chicago that year.
It became a perennial best seller, spawning several sequels, and was animated by Disney as part of the feature anthology Melody Time.
During World War II, he worked in Hollywood producing training films for the United States Army Air Forces.
He continued working as a commercial illustrator producing art for Fortune, Collier's, Woman's Day, True, American and Reader's Digest.