In 1901, Onderdonk enrolled at the New York Art Student's League to broaden his artistic education. With the encouragement of his father, he joined William Merritt Chase's Shinnecock Summer School of Art in Southampton, Long Island, which Chase had established in 1891. After 1902, Onderdonk left the League and enrolled in Chase's New York School of Art.

Chase was a mentor and kindred spirit to Julian Onderdonk who like his teacher, favored painting images directly from nature, using vivid colors and heavy impasto. Shinnecock, with its sweeping vista, illustrates Onderdonk's fascination with landscape, lush color and the effects of light. The artist remained in New York until 1909 when he returned to his native Texas.