Also that year, Benjamin Harrison had been inaugurated as president and selected a friend of Grubb, James G. Blaine, as secretary of state. Blaine arranged for Grubb to be one of Harrison's seven appointees to the 1890 Board of Visitors to West Point Military Academy; he was elected vice president. Among other things, his committee suggested the purchase of the Academy's first Hotchkiss gun. Blaine then arranged for Grubb to be appointed as Ambassador to Spain. During his term, he negotiated a trade reciprocity treaty. In 1892, he resigned and returned to New Jersey.