Justin Sholly, 29, was arrested and faces several felony arson charges on Tuesday.
He worked for the Perseverance Volunteer Fire Company, according to officials.
Investigators say he allegedly set three fires in Souderton and Franconia Township late last month, all within about 24 hours.
In each case, investigators say Sholly would then respond with his fire company to put them out.
Two barns and several vehicles were damaged.
Police say license plate readers helped them identify Sholly as the suspect.
They also say he allegedly admitted to the arsons after being confronted.
He allegedly used fire starter logs, which were found in his vehicle.