In 1955, Gray was appointed Special Assistant for Manpower for the United States Department of the Navy, the following year, Gray served as Appointments Secretary to President Dwight Eisenhower and later as Secretary of his cabinet.
Private sector
He taught business administration at Nebraska's Hastings College. In the 1960s and 1970s, he served as Washington operative for Hill & Knowlton. In those years, according to a case study by the Harvard Business School, H&K's clients produced nearly 10% of the GNP. Gray provided services to accounts that included the American Petroleum Institute, Procter and Gamble, and the National Association of Broadcasters and El Paso Natural Gas. El Paso hired Hill and Knowlton to drum up support for legislation that would allow El Paso to buy out its competitor, Pacific Northwest Pipeline Company. In 1967, Gray joined the 50-person committee responsible for charting Richard Nixon's path to the White House. After Nixon was elected president, Gray would often escort Nixon's personal assistant, Rose Mary Woods to official functions. After serving as deputy director of the Reagan-Bush presidential campaign, in 1980, Gray became Reagan's first appointment as president when Gray was named co-chairman of Ronald Reagan’s Presidential inauguration. During the Reagan Administration, Gray started his own firm, Gray and Company, in 1981. When he took the firm public in 1985, it became the first public relations-public affairs firm to be listed on the New York Stock Exchange. Three years later, he sold majority interest in the firm to Hill & Knowlton and became H&K's Worldwide Chairman. In 1988, as one of his last acts as president, Reagan flew to Gray's hometown, Hastings, Nebraska, to dedicate a communications center Gray had given to Hastings College in honor of his parents. Notable clients of Gray and Company included Adnan Khashoggi, Saudi Arabian billionaire and arms dealer, the government of Haiti under the Duvalier dynasty, American commodities trader and financier Marc Rich, the Teamsters Union, and Korean religious leaderSun Myung Moon. Gray’s first book, Eighteen Acres Under Glass: Life in Washington As Seen By the Former Secretary of the Cabinet, was published in 1962 by Doubleday in the States and by MacMillan overseas. Eventually becoming number four on The Times best-seller list, the book highlighted the demands on both his political and social life as the Secretary of the Cabinet under President Dwight D. Eisenhower. With tales from the visits with kings and queens to the extended hours spent with the Chief Executive, the book gives an inner look at the functions and sometimes dysfunctions of Washington. Gray was featured in cover stories in Time magazine and U.S. News & World Report, and was the subject of a fifteen-minute Monitor program on NBC. The 1992 book, The Power House: Robert Keith Gray and the Selling of Access and Influence in Washington by Susan B. Trento, "tells how Mr. Gray, after unabashedly peddling access for decades, reached the apex of his influence when his friend Ronald Reagan moved into the White House." In 2012 Gray's book Presidential Perks Gone Royal: Your Tax Dollars Are Being Used For Obama's Re-Election was published by New Voices Press.