Police arrested Edward Marquette and charged him with third-degree assault and second-degree unlawful imprisonment, both misdemeanors.
At about 5:30 p.m., police responded to a call about a distraught woman in front of the Scotia- Glenville High School.
The woman whom police identified as Marquette's girlfriend accused him of trying to restrain her inside his truck, town police said.
While in the truck, police said, Marquette allegedly put sunscreen in the woman's eyes. When she fled, he allegedly threw her against a tree and stepped on her wrist.
Police found Marquette, who was promoted to the position of deputy chief in 1998, and the victim at the school.
Scotia Fire Department members treated the woman at the scene.
Schenectady Fire Chief Robert Farstad said he knew about the arrest but "wouldn't speculate" as to what action the department might take.
Farstad said more information will be available today or Tuesday.
Marquette was arraigned before Town Justice Dennis Englert, ordered to reappear July 6 and released.
