Power of Attorney for Robert O'Shaughnessy

This filing is an Exhibit 24.1, a Power of Attorney granted by Robert O'Shaughnessy, an officer and/or director of CarMax Inc. (KMX), to John M. Stuckey III, Terence Rasmussen, Christine Carter, and Chelsea Shrader. The attorneys-in-fact are authorized to execute and file Forms 3, 4, and 5, or any amendments, in accordance with Section 16(a) of the Securities Exchange Act of 1934. They are empowered to take any action deemed beneficial, in the best interest of, or legally required for the undersigned. The Power of Attorney remains in effect as long as O'Shaughnessy is required to file these forms. The filing is dated March 23, 2026, with the signature date as June 23, 2026.