Christopher Williams
NASA portrait, 2021
Born	Christopher Leigh Williams 1983 (age 41–42) New York City, New York, U.S.
Education	Stanford University (BS) Massachusetts Institute of Technology (MS, PhD)
Space career
NASA astronaut
Selection	NASA Group 23 (2021)
Scientific career
Fields	Physics
Thesis	Initial Exploration of 21-cm Cosmology with Imaging and Power Spectra from the Murchison Widefield Array (2012)
Doctoral advisor	Jacqueline Hewitt

Christopher Leigh Williams is an American medical physicist and NASA astronaut. He resides in Boston, Massachusetts.

Williams grew up in Potomac, Maryland. He graduated from Montgomery Blair High School, Silver Spring, Maryland in 2001. He graduated from Stanford University in 2005 with a bachelor's degree in physics and a doctorate in physics from MIT in 2012, where his research was in astrophysics. Williams is a board-certified medical physicist, completing his residency training at Harvard Medical School before joining the faculty as a clinical physicist and researcher.^[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. He was the lead physicist for the Institute's MRI-guided adaptive radiation therapy program. His research focused on developing image guidance techniques for cancer treatments.^[4][2]

On December 6, 2021, Williams was selected to join NASA Astronaut Group 23 candidate class.^[5]