The Friends of the Angeles began as an informal coalition of groups and individuals united around a common vision of the Angeles National Forest as a thriving forest with healthy watersheds and sustainable recreation, supported by an active, engaged, and diverse community. The coalition was established in August 2012, with support from the National Forest Foundation and the Angeles National Forest.
The Friends of the Angeles was formalized in 2014 with the signing of a charter by six founding parties: Amigos de los Rios, the California Trail Users Coalition, Rancho Santa Ana Botanic Garden, REI, Southern California Edison, and Jack Sahl. The following parties were named in the charter as ex officio members: Rivers and Mountains Conservancy, South Coast Air Quality Management District, National Park Service/Santa Monica Mountains National Recreation Area, and the Forest Service (Southern California Consortium and the Angeles National Forest). The National Forest Foundation served as fiscal sponsor for the organization.
On October 10, 2014, President Barack Obama designated a portion of the Angeles National Forest as the San Gabriel Mountains National Monument. This presented an opportunity and need for the Friends of the Angeles to refocus its mission to include serving the newly designated Monument and the surrounding communities. Soon after, the founding members voted to become a 501(c)(3) nonprofit organization. Coalition Chair Jack Sahl agreed to lead the organizational transition. On behalf of the Friends of the Angeles, he applied for California Public Benefit Corporation and US IRS 501(c)(3) charitable status in January 2015.