Christopher Leigh Williams is an American medical physicist and NASA astronaut.

He graduated from Montgomery Blair High School, Silver Spring, Maryland in 2001.

[1][2] Before his Ph.D., Williams worked at the United States Naval Research Laboratory and NASA's Goddard Space Flight Center, as well as volunteered as an EMT and firefighter for the Rockville Volunteer Fire Department serving Montgomery County, Maryland.

[3] He most recently worked as a medical physicist in the Radiation Oncology Department at the Brigham and Women's Hospital and Dana-Farber Cancer Institute in Boston.

[4][2] On December 6, 2021, Williams was selected to join NASA Astronaut Group 23 candidate class.