Pi Kappa Phi fraternity was founded in the spirit of "nu phi," meaning non-fraternity, in the year 1904. Several students at the College of Charleston in South Carolina came together to form a slate to oppose a group of fraternity men in an election. Although the "nu phi" slate lost (in part because some members of the slate did not vote as they had promised), many of the men came together to form Pi Kappa Phi on December 10, 1904.

By 1907, Pi Kappa Phi had become a national fraternity by establishing a chapter at the University of California in Berkeley. Today, Pi Kapp is a leading national fraternity, with over 90,000 men initiated. The national organization has been one of the most progressive and active of all fraternities, taking strong stances against hazing and sexual assault. Pi Kappa Phi is the only national fraternity with its own exclusive philanthropy, Push America, founded in 1977. Push America's goal is to help those with disabilities while spreading awareness and empathy. UCLA's Eta Sigma chapter operates with Push as an integral part of its yearly activities.