Dozens of chefs and people worked at the Auto Club Speedway of California in Fontana to make the pizza, which broke the previous record when it reached the length of 6,333 feet or 1.93 km.
Representatives from the Guinness World Records certified it as the world's longest, reports Efe news.
Once it was set on one of the largest scaffolding units ever made, the pizza weighed 7,808 kg.
It was prepared with around 3,632 kg of dough, 1,634 kg of cheese and 2,542 kg of salsa sauce.
As part of the procedure, three industrial ovens which worked non-stop for eight hours were used.
The ovens had to be shifted every 17 minutes by experts and volunteers.
The free-for-all event was advertised as "a reason to celebrate humanity and friendship".
All of the earnings of the event will be donated to local food banks and homeless shelters.