He holds a BA in history and political science from Willamette University and a JD from Baylor Law School (1987).

After a two-year post in Japan he returned to Washington to work in the Office of Japanese Affairs on environmental and health issues.

He returned to Washington in summer 2003 for a year of Thai language training and was posted to Bangkok in 2004 to focus on US-Thailand political and military relations.

[6][7] Most recently he served as Deputy Assistant Secretary of State for Japan, Korea, Mongolia, Australia, New Zealand, and the Pacific Islands.

[2][8] In September 2023, the State Department announced that Lambert would succeed Rick Waters as China Coordinator heading the Office of China Coordination and serve as Deputy Assistant Secretary of State in the Bureau of East Asian and Pacific Affairs.