According to investigators, Javier Adolfo Viera, 35, admitted to setting several fires in the area over the past five months. Authorities also found corroborating evidence at his home.
Since November, there have been 21 incidents of arson or attempted arsons in the city of South Pasadena and four in Pasadena, officials said.
Authorities said Viera was under surveillance when they arrested him for a car fire on the 6100 block of Oak Hill Avenue in Los Angeles.
Officials said the crimes began with small vegetation fires, but they escalated to car fires as well as the exterior door of a business.
The break came when fingerprints recovered from an incendiary device allegedly linked Viera to the fires.