The following year Van de Kamp went to the Lick Observatory in California as a Kellogg fellow. There he received his PhD from the University of California in Astronomy in June 1925. The next year he also received a PhD from the University of Groningen. Van de Kamp returned to McCormick on October 1, 1925 to take up the position left vacant by Harold Alden, who had just taken up the directorship of the Yale University Observatory Southern Station in Johannesburg, South Africa. In the spring of 1937, Van de Kamp left McCormick Observatory to take over as director of Swarthmore College's Sproul Observatory. One of his early pupils in astrometry was Nancy Grace Roman, who went on to become NASA's first Chief of Astronomy.