Seiple succeeds Keith Garrity, who retired after 30 years with the department, including 10 years as chief.
Seiple, who had been the department's assistant chief the past five years, is fulfilling his career dreams, according to the post. He has been with the department for 14 years.
Garrity had moved through the rank to reach the top spot as chief. He spent a lot of his early years riding trucks and training, the website said.
The department will hold an election in December to fill the open position of 2nd assistant chief.