Representative Krishnamoorthi is the child of immigrants and was raised in Peoria, Illinois. He attended public schools in Peoria and was a valedictorian of his high school class. Scholarships and student loans allowed him to graduate summa cum laude from Princeton University with a degree in mechanical engineering and a certificate from the Princeton School of Public and International Affairs. He then graduated with honors from Harvard Law School and clerked for a federal judge before practicing law in Chicago.

Representative Krishnamoorthi pursued public service while practicing law and was appointed by Illinois Attorney General Lisa Madigan as a Special Assistant Attorney General to help start the state's Public Integrity Unit created to root out corruption in Illinois. As a member of the Illinois Housing Development Authority, the Congressman chaired the Audit Committee, helping to provide thousands of low and moderate-income families across the state with affordable housing. Congressman Krishnamoorthi also served as Illinois Deputy Treasurer, where he oversaw the state's technology venture capital fund and helped make programs such as the state's unclaimed property program leaner and more efficient.

After his time in the Illinois Treasurer's Office, Representative Krishnamoorthi returned to the private sector, serving as president of research-oriented small businesses developing technology in the national security and renewable energy industries. Representative Krishnamoorthi also served as the Vice-Chair of the Illinois Innovation Council and co-founded InSPIRE, a non-profit that provides inner-city students and veterans with training in solar technology.

The Congressman resides with his wife Priya, a physician, and 3 children in Schaumburg, Illinois.