Lake was born in New York City graduated from Harvard in 1961. He studied economics at Trinity College, Cambridge and later received a PhD from the Woodrow Wilson School of Public and International Affairs at Princeton University in 1974.
Lake joined the State Department in 1962 as an assistant to Ambassador Henry Cabot Lodge during the Vietnam War. His State Department career included assignments as consul in Saigon (1963), vice consul in Hue (1964-65) and special assistant to the assistant to the president for National Security Affairs (1969-1970) in the Nixon administration. In 1969, he accompanyied Secretary of State Henry Kissinger on first secret meeting with North Vietnamese negotiators in Paris. In 1970, he had a falling out with Kissinger over the Nixon administration's extension of the war to Cambodia and later wrote a book critical of Kissinger's approach to Africa.
After work for Maine Senator's Edmund Muskie's presidential campaign and a stint at the Carnegie Endowment and International Voluntary Services, Mr. Lake returned to the State Department in 1977 to serve as director of policy planning for President Carter, a position he held until 1981.
When Ronald Reagan came into office in 1981, Lake withdrew into academia, becoming a professor at Amherst College in Massachusetts. In 1984, he moved to Mount Holyoke College, where he has taught courses in the Vietnam War, Third World revolutions, and American foreign policy. During the 1992 presidential campaign, he was one of candidate Clinton's chief foreign policy advisers. (Clinton and Lake had worked together in the 1972 presidential campaign of George McGovern.)