Mount Nittany Medical Center said Paterno died of metastatic small cell carcinoma of the lung, an aggressive cancer that had spread.
Friends and former colleagues believe there were other factors - the kind that wouldn't appear on a death certificate.
"You can die of heartbreak," said Bobby Bowden, the former Florida State coach who retired two years ago after 34 seasons in Tallahassee.
Longtime Nebraska coach Tom Osborne said he suspected "the emotional turmoil of the last few weeks might have played into it."
Mickey Shuler, who played tight end for Paterno from 1975 to 1977, held his alma mater accountable: "I don't think that the Penn State that he helped us to become and all the principles and values and things that he taught were carried out in the handling of his situation."
A startling fall
The winningest coach in major college football, Paterno roamed the Penn State sidelines for 46 seasons, his thick-rimmed glasses, windbreaker and jet-black sneakers as familiar as the Nittany Lions' blue and white uniforms.
His devotion to what he called "Success with Honor" made Paterno's fall all the more startling.
In the middle of his final season, Paterno was engulfed in a child sex abuse scandal when a former trusted assistant, Jerry Sandusky, was accused of molesting 10 boys over a 15-year span, sometimes in the football building.
Outrage built quickly after the state's top law enforcement official said Paterno hadn't fulfilled a moral obligation to go to authorities when a graduate assistant, Mike McQueary, reported seeing Sandusky with a young boy in the showers of the football complex in 2002.
Paterno waited a day before alerting school officials and never went to the police.
"I didn't know which way to go," Paterno told The Washington Post in an interview nine days before his death.
"You know, (McQueary) didn't want to get specific," Paterno said. "And to be frank with you I don't know that it would have done any good, because I never heard of, of, rape and a man. So I just did what I thought was best. I talked to people that I thought would be, if there was a problem, that would be following up on it."
When the scandal broke in November, Paterno said he would retire following the 2011 season. He also said he was "absolutely devastated" by the abuse case.
"This is a tragedy," he said. "It is one of the great sorrows of my life. With the benefit of hindsight, I wish I had done more."
But the university trustees fired Paterno, effective immediately.
Paterno was notified by phone, not in person, a decision that board vice chairman John Surma regretted, trustees said.
After weeks of escalating criticism by some former players and alumni, trustees last week said they fired Paterno in part because he failed a moral obligation to do more in reporting the 2002 allegation.
An attorney for Paterno on Thursday called the board's comments self-serving and unsupported by the facts. Paterno fully reported what he knew to the people responsible for campus investigations, lawyer Wick Sollers said.
"He did what he thought was right with the information he had at the time," Sollers said.
'He died as he lived'
Paterno's death came just 65 days after his son Scott said his father had been diagnosed with lung cancer.
Paterno had been in the hospital since Jan. 13 for observation after what his family called minor complications from his cancer treatments.
Not long before that, he conducted his only interview since losing his job, with The Washington Post. Paterno was described as frail then, speaking mostly in a whisper and wearing a wig. The second half of the two-day interview was conducted at his bedside.
Paterno's family released a statement Sunday morning to announce his death: "His loss leaves a void in our lives that will never be filled."
"He died as he lived," the statement said. "He fought hard until the end, stayed positive, thought only of others and constantly reminded everyone of how blessed his life had been. His ambitions were far reaching, but he never believed he had to leave this Happy Valley to achieve them. He was a man devoted to his family, his university, his players and his community."
Paterno's death just under three months following his last victory called to mind another coaching great, Alabama's Paul "Bear" Bryant, who died less than a month after retiring.
"Quit coaching?" Bryant said late in his career. "I'd croak in a week."
Paterno alluded to the remark made by his friend and rival, saying in 2003: "There isn't anything in my life anymore except my family and my football. I think about it all the time."
'Success with Honor'
Paterno built a program based on the credo of "Success with Honor," and he found both. The man known as "JoePa" won 409 games and took the Nittany Lions to 37 bowl games and two national championships. More than 250 of the players he coached went on to the NFL.
"He will go down as the greatest football coach in the history of the game," Ohio State coach Urban Meyer said after his former team, the Florida Gators, beat Penn State 37-24 in the 2011 Outback Bowl.
The reputation he built looked even more impressive because he insisted that on-field success not come at the expense of high graduation rates.
Paterno believed success was not measured entirely on the field. From his idealistic early days, he implemented what he called a "grand experiment" - to graduate more players while maintaining success on the field.
Ethics and education
Paterno was a frequent speaker on ethics in sports, a conscience for a world often infiltrated by scandal.
The team consistently ranked among the best in the Big Ten for graduating players. As of 2011, it had 49 academic All-Americans, the third-highest among schools in the Football Bowl Subdivision. All but two played under Paterno.
"He teaches us about really just growing up and being a man," former linebacker Paul Posluszny, now with the NFL's Jacksonville Jaguars, once said. "Besides the football, he's preparing us to be good men in life."
Paterno's critics were in the minority, and his program was never cited for major NCAA violations. The child sex abuse scandal, however, did prompt separate inquiries by the U.S. Department of Education and the NCAA into the school's handling.
Early years
Paterno played quarterback and defensive back for Brown University and set a defensive record with 14 career interceptions, a distinction he still boasted about to his teams when he was in his 80s. He graduated in 1950 with plans to go to law school. He said his father hoped he would someday be president.
But when Paterno was 23, a former coach at Brown was moving to Penn State to become the head coach and persuaded Paterno to come with him as an assistant.
"I had no intention to coach when I got out of Brown," Paterno said in 2007 in an interview at Penn State's Beaver Stadium before being inducted into college football's Hall of Fame. "Come to this hick town? From Brooklyn?"
In 1963, he was offered a job by the late Al Davis - $18,000, triple his salary at Penn State, plus a car to become general manager and coach of the AFL's Oakland Raiders. He said no.
Rip Engle retired as Penn State head coach three years later, and Paterno took over.
At the time, Penn State was considered "Eastern football" - inferior - and Paterno courted newspaper coverage to raise the team's profile. In 1967, Penn State began a 30-0-1 streak.
But the Nittany Lions couldn't get to the top of the polls. They finished second in 1968 and 1969 despite perfect seasons. They were undefeated and untied again in 1973 at 12-0 again but finished sixth. Texas edged them in 1969 after President Richard Nixon, impressed with the Longhorns' bowl performance, declared them No. 1.
"I'd like to know," Paterno said later, "how could the president know so little about Watergate in 1973, and so much about college football in 1969?"
A national title finally came in 1982, after a 27-23 win over Georgia at the Sugar Bowl. Another followed in 1986 after the Lions intercepted Vinny Testaverde five times and beat Miami 14-10 in the Fiesta Bowl.
They made several title runs after that, including a 2005 11-1 season and a run to the Orange Bowl and an 11-2 season in 2008 that ended in a 38-24 loss to Southern California in the Rose Bowl.
Later in life
In his later years, physical ailments wore the old coach down.
Paterno was run over on the sideline during a game at Wisconsin in November 2006 and underwent knee surgery. He hurt his hip in 2008 demonstrating an onside kick. An intestinal illness and a bad reaction to antibiotics prescribed for dental work slowed him for most of the 2010 season. He began scaling back his speaking engagements that year, ending his summer caravan of speeches to alumni across the state.
Then a receiver bowled over Paterno at practice in August, sending him to the hospital with shoulder and pelvis injuries and consigning him to coach much of his last season from the press box.
"The fact that we've won a lot of games is that the good Lord kept me healthy, not because I'm better than anybody else," Paterno said two days before he won his 409th game and passed Eddie Robinson of Grambling State for the most in Division I. "It's because I've been around a lot longer than anybody else."
Paterno could be conservative on the field, especially in big games, relying on the tried-and-true formula of defense, the running game and field position.
Behind the scenes
He and his wife, Sue, raised five children in State College. Anybody could phone him at home by looking up "Paterno, Joseph V." in the phone book.
He walked to home games and was greeted and wished good luck by fans on the street. Former players paraded through his living room for the chance to say hello. But for the most part, he stayed out of the spotlight.
Paterno did have a knack for jokes. He referred to Twitter, the social media site, as "Twittle-do, Twittle-dee."
He also could be abrasive and stubborn, and he had his share of run-ins with bosses and administrators. And as his legend grew, so did the attention to his on-field decisions, and the questions about when he would hang it up.
Calls for his retirement reached a crescendo in 2004. The next year, Penn State went 11-1 and won the Big Ten. In the Orange Bowl, Penn State beat Florida State, whose coach, Bobby Bowden, was eased out after the 2009 season after 34 years and 389 wins.
Like many others, he was outlasted by "JoePa."
Loss of an icon
New Penn State football coach Bill O'Brien, hired earlier this month, offered his condolences.
"The Penn State Football program is one of college football's iconic programs because it was led by an icon in the coaching profession in Joe Paterno," O'Brien said in a statement. "Our families, our football program, our university and all of college football have suffered a great loss, and we will be eternally grateful for Coach Paterno's immeasurable contributions."
