Police were alerted to Gallagher's offer early Sunday morning and got a description of him from the worker.
A police department in Florida says a 23-year-old went through a fast-food chain drive-through and tried to pay for his order with a bag of marijuana.
Not much later, the suspect went through the drive-thru again.
The employee then called Port St Lucie Police and gave officers a description of the driver, before a suspect matching his description came through a second time a little while later.
"PSLPD officer made contact with the suspect and noticed a heavy odor of marijuana emitting from the vehicle", they wrote. The man was allegedly found with about 11 grams of marijuana in the vehicle. He was taken to Lucie County Jail for booking.
Gallagher later failed a field sobriety test, police said. The auto was described as "excessively dirty" and littered with french fries, chicken nuggets and moldy chicken wings.
Gallagher is facing several charges including possession of marijuana and DUI.
The local police department posted the suspect's mugshot to its Facebook page on Sunday.