Authorities said they took Harry Burkhart into custody without incident shortly after 3 a.m. in the city's Hollywood district. He subsequently was charged with one count of arson and is being held without bail.
Our long four-day nightmare is over," said Zev Yaroslavsky, a Los Angeles County supervisor. "I haven't had a good night's sleep since last week. I'm looking forward to one tonight."
The arrest is a breakthrough in a four-day string of 53 suspicious fires that broke out in and around Los Angeles, many in or near Hollywood, causing damage of about $3 million. One injured firefighter was treated and released in good condition, and another person suffered from smoke inhalation.
The rash of fires prompted a heavy police presence, including helicopter surveillance, in and around the popular tourist area over the long holiday weekend.
The detention followed the Sunday release of security-camera footage of a person sought in connection with the fires. The grainy video showed a man, dressed in black, with a receding hairline and dark shoulder-length hair pulled into a ponytail.
At a Monday evening news conference, authorities said a reserve sheriff's deputy, Shervin Lalezary, who spotted Mr. Burkhart sitting in a van, recognized him from the security footage. Mr. Burkhart's van had Canadian license plates.
Mr. Burkhart, who told investigators he was from Frankfurt, Germany, was detained at about 3 a.m. He was arrested under 451.b of the penal code, which covers arson and reckless burning, police said.
Given his stocky appearance and hairstyle in the security-video footage, Mr. Burkhart was nicknamed "Meatloaf Seagal" by users of the microblogging site Twitter, a reference to the singer Meat Loaf and action-movie actor Steven Seagal.
Nine of the latest fires occurred in the city of Los Angeles and two occurred in neighboring West Hollywood, according to police.
Police have said they believe the fires may have been set by two unrelated groups.
After an outbreak of fires on Thursday, authorities arrested two men, but said at the news conference Monday that they didn't believe those two were connected to Mr. Burkhart.
Many of the fires targeted cars parked underneath low-rise, garden-style apartments. In some cases, as the vehicles burned, the fires spread to the adjacent structures.
Police say they are pursuing hundreds of clues and speaking with many witnesses as part of the investigation.
Danny Grois, a 21-year-old pharmacy employee, said he was spooked by two attacks spaced a few hours apart. Mr. Grois captured on video both of the fires—one across the street from his apartment in West Hollywood and the other in the parking structure of his Hollywood workplace.
"It's scary," Mr. Grois said, displaying video of the incidents. "It happened to me twice."
The fire spree didn't disturb everyone. Many tourists, who enjoyed sunny skies and temperatures above 80 degrees, said they were unaware of the blazes.