Two men and two women were taken to hospital with life-threatening injuries after the incident in Lafayette Square on Thursday evening (local time).
The lightning struck the four people near a tree that stands yards away from a fence that surrounds the US presidential residence and offices.
Officers with the Secret Service and US Park Police witnessed the lightning strike and ran over to offer first aid, the District of Columbia Fire and Emergency Medical Services Department said.
Their quick actions were praised by officials.
Local news weather cameras recorded a violent lightning strike around the time of the incident.
Four people were critically injured by a lightning strike Thursday evening near the White House. A camera near Lafayette Park captures a violent strike about the same time the victims were struck. All four were unconscious when U.S. Park Police arrived on the scene. pic.twitter.com/Hdkpdi5qGq
— Dan Henry (@Fox4Weather) August 5, 2022
Emergency services were called to the scene just before 7pm and transported the victims to the hospital with "critical, life-threatening injures," fire department spokesman Vito Maggiolo said.
A portion of the park remained closed for more than an hour.
Lafayette Square is a seven-acre public park located within President’s Park, directly north of the White House.
It is often is crowded with visitors, especially in the summer months.
Temperatures in Washington exceeded 32C on Thursday, although, with the high humidity, forecasters said it felt warmer.
A violent thunderstorm swept through the capital late in the day.