Sterling founded the University of Phoenix to accommodate older students who wanted to advance their education but didn't have time for a typical classroom schedule. He built his schools near highways and busy intersections and scheduled evening classes.
"He was trying to provide a service that the private sector was not interested in doing," said University of Southern California professor William G. Tierney, who authored "New Players, Different Game: Understanding the Rise of For-Profit Colleges and Universities."
Sperling once said to Tierney: " 'I had one good idea, but it was a darn good idea,' " he recalled.
The University of Phoenix's reputation has suffered in the past few years as federal regulators reviewed its financial aid practices, and as criticism of for-profit colleges and how they attract students grew louder.
Tierney, however, said that misses the bigger picture of Sperling's contributions to education.
"What people have made of it, including the University of Phoenix, is different than someone who invented an idea and moved forward with it," he said.
Sperling's son, current Chairman Peter Sperling, and Chief Executive Officer Greg Cappelli said in a statement on the Apollo website that John Sperling made higher education more accessible to adult students.
The University of Phoenix has a presence in 38 states and in Puerto Rico, and at one point touted 470,000 students, although that number has significantly dropped.
It was a long road for Sperling, who received an undergraduate degree from Reed College and later earned a fellowship at King's College at the University of Cambridge and obtained a doctorate in 18th century English mercantile history in 1955.
In 1972, after years of teaching history at San Jose State University, Sperling founded his first company, the Institute for Professional Development. It worked mostly with Jesuit universities to create degree programs for working adults.
The programs didn't prove too popular at most universities, and Sperling headed to Arizona, where he founded the University of Phoenix in 1978.
Sperling used his wealth on several philanthropic projects, including research into seawater agriculture and anti-aging medicine. He was also an outspoken critic of the government's war on drugs, advocating for treatment instead of criminalization.
He valued his education roots the most.
"University of Phoenix is my proudest legacy," Sperling said in a 2011 interview with The Arizona Republic. "Knowing that over 1 million staff, faculty and students have benefited in some way from the university is something I'm very proud of."