[1] It was created in 1998 by gardener Sonny Klamerus, a resident of neighboring Northridge, Los Angeles, who originally trespassed on the property in order to gain access, and considered it a "practical joke."
[3] Klamerus claims to have made Happy Face Hill in 1998 as a prank and trespassed on land owned by a development company to create the work.
[5][6] The Hill has undergone several notable changes, with the addition of solar-powered lights, an adjustment in the angle of the smile, and spotlights aimed at the hillside.
In anticipation for the festival celebrating the 50th Anniversary of Little House on the Prairie, the hill was covered in thousands of blue and yellow flags.
[7][8] The Hill is currently maintained by members of the Simi Valley Sunrise Rotary Club,[9] who also produce an annual Happy Face Music Festival in reference to the landmark.