#2 Randy Orton
Randy Orton won his first, and only, WWE United States Championship at Fastlane in 2018. By defeating Bobby Roode at the event, The Viper became the 18th Grand Slam Champion in WWE history.
However, Randy Orton's first WWE United States Championship reign would be short-lived. Orton lost the United States Championship to Jinder Mahal at WrestleMania 34 in a Fatal 4-Way match. Therefore, The Apex Predator's first and only United States Championship reign only lasted 28 days.
With Jinder Mahal's victory and subsequent defeat to Jeff Hardy 8 days later on Raw, the United States Championship had changed hands 4 times in 4 months on WWE television.
Due to the nature of the WWE United States Championship having multiple different champions in such a short period of time, with every champion having short title reigns, as well as switching brands from Smackdown to Raw during this time, many of title reigns are often overlooked and forgotten.
Therefore, many members of the WWE Universe often forget that Randy Orton even held the WWE United States Championship in the first place.