The crash happened before 4:20 p.m. Thursday near Skirball Center Drive in the Sepulveda Pass during the afternoon rush hour.
Details on what led up to the crash were not immediately available, but it appeared a Tesla vehicle was involved.
Aerial footage showed paramedics treating the injured officer in the middle of the freeway. The officer was loaded into an ambulance and taken to a hospital in unknown condition.
Traffic was backed up for miles during the shutdown and later on when some lanes reopened.