James A. Isenberg (born 1951) is an American theoretical physicist and mathematician, professor emeritus at the University of Oregon.

[2] When he ran the Boston Marathon at age 18, The Philadelphia Inquirer reported he "is 5 feet 1 inch tall, weighs 95 pounds and looks about 13.

He was a graduate student under Charles Misner at the University of Maryland, and he earned Ph.D. in physics in 1979, with his dissertation, Construction of Spacetimes from Initial Data.

[6] In Australia in 2017, Isenberg was standing in the ocean when a wave knocked him over, injuring his spinal cord and leaving him paralyzed from the neck down.

[11] Isenberg was elected a Fellow of the American Physical Society in 2000, cite "For his pioneering work on global issues in general relativity and for his contributions to the field.