Manuel Castro, 30, was booked on suspicion of vandalism on Wednesday night, the Los Angeles Times reported.
"Everybody is entitled to free speech, but it seems like for the gay tribe, this is more of an issue of equal rights -- human rights," Castro told The Huffington Post.
The painted words were accompanied by a cow holding a paint brush.
A second person may have been involved in commissioning the piece of art, and investigators are searching for a person of interest, the Times reported.
Castro's website says the L.A.-based artist's work has included "hanging thousands of Ruby Slippers over power lines throughout the city and installing over-sized simulated cocaine bags on telephone poles around major intersections.
On his Twitter page, Castro retweeted messages from followers thanking him for the public display.
"You're the man!!! Thank you for standing up and speaking out!" said one tweet.
"You are a hero," said another.
The graffiti in Torrance appeared on the morning of August 3, the same day that gay rights activists staged a "same sex kiss day" at Chick-fil-A restaurants nationwide.
Activists asked couples to go to one of the chicken chain's locations and take a photo or video of themselves kissing for an event they called "National Same-Sex Kiss Day."
"National Same-Sex Kiss Day" followed Wednesday's "Chick-fil-A Appreciation Day," in which Americans lined up at eateries nationwide to support the company.
The controversy was started after statements made in July by Cathy during an interview with The Baptist Press.
"We are very much supportive of the family - the biblical definition of the family unit," Cathy said. "We are a family-owned business, a family-led business, and we are married to our first wives. We give God thanks for that."
Former Arkansas Gov. Mike Huckabee then fueled the national debate, calling for those against gay marriage to rush to the restaurant on Wednesday to show solidarity with Cathy's statements.
The restaurant, which claims no involvement in Huckabee's event, says it set a sales record that day, even selling out at many locations.