Philanthropist William Seegmiller previously oversaw his own law firm in Newport Beach, California, where he successfully represented clients in a wide range of personal injury and wrongful death matters. His commitment to helping others has extended to his involvement in multiple philanthropic efforts. For instance, William Seegmiller supported the 9/11 Victims Federal Relief Fund as a member of Trial Lawyers Care. He also delivered a presentation on the exploitation of foreign workers at the Global Entrepreneurship Initiative.

A charitable individual, he regularly donates to the Special Olympics and volunteers with The Reinhart Foundation. Moreover, Seegmiller contributes to legal scholarships at the Thomas Jefferson School of Law and Pepperdine University School of Law and sponsors a ballerina at the Bolshoi Ballet.

Additionally, William Seegmiller combines his passion for travel with his charitable endeavors by embarking on personal missions to aid people from underserved communities in Guatemala and Cuba. During these missions, he has provided water purifiers, stoves, and medical and dental supplies to families in need.