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NEW ORLEANS, LA – JANUARY 28: San Francisco 49ers defensive end Aldon Smith speaks with the media during a media availability session for Super Bowl XLVII at the New Orleans Marriot on January 28, 2013 in New Orleans, Louisiana. (Photo by Stacy Revere/Getty Images)
The cause of death for former San Francisco 49ers star Aldon Smith has not been released, but his family is now pursuing answers through a posthumous brain examination.
Smith’s family has decided to send his brain to medical experts in Boston to determine whether chronic traumatic encephalopathy, known as CTE, played a role in his death, according to ESPN’s report. Smith died Saturday, June 13, at age 36, hours after delivering pizzas to a homeless charity.
“As with anyone who dies so suddenly at such a young age, we understand that there is a great deal of interest in and speculation about Aldon Smith’s passing and we intend to get to the bottom of it,” attorneys Harry Daniels, Bakari Sellers and Wayne Kendall said in a statement, per ESPN.
The attorneys said Smith’s brain was being sent to Boston, where medical experts will examine it for CTE “as well as other damage caused by years of concussions and additional trauma.”
The step does not mean CTE has been diagnosed. It also does not establish Smith’s cause of death. The Santa Clara County Medical Examiner has not publicly announced a cause of death, and Smith’s family is asking for privacy while it seeks more information.
Aldon Smith’s Family Is Seeking Answers After Sudden Death
The CTE examination is significant because Smith’s family says the former 49ers pass rusher suffered numerous concussions during his NFL career, according to ESPN.
CTE is a degenerative brain disease associated with repetitive head trauma. Boston University’s CTE Center says the condition is linked to repetitive brain trauma, including concussions and non-concussive head impacts, though researchers still do not know exactly how many hits or what type of hits can trigger the disease.
CTE can only be definitively diagnosed after death through examination of brain tissue, according to Mayo Clinic.
For the 49ers, Smith’s death is both a tragedy and a reminder of one of the most complicated careers in recent franchise history. He was one of the most explosive young defensive players the team has ever had, and his early NFL production still stands out more than a decade later.
The 49ers confirmed Smith’s death and said they were “devastated” by the news. The team noted that Smith appeared in 50 games for San Francisco, recording 152 tackles, 44 sacks, five forced fumbles and 5.5 sacks in eight postseason games.
Aldon Smith Still Owns a Major 49ers Franchise Record
Smith’s football peak came fast.
The 49ers selected him with the No. 7 overall pick in the 2011 NFL draft out of Missouri. As a rookie, he posted 14 sacks and 27 quarterback hits, finishing second in Defensive Rookie of the Year voting.
A year later, Smith delivered one of the best pass-rushing seasons in 49ers history. He recorded 19.5 sacks in 2012, earning Pro Bowl and first-team All-Pro honors while helping San Francisco reach Super Bowl XLVII. That 19.5-sack season remains the franchise’s single-season record.
Smith’s 33.5 sacks through his first two NFL seasons also remain one of the most staggering starts by a defensive player in league history. StatMuse lists Smith as having the most sacks by any player in his first two seasons since sacks became an official stat in 1982.
That dominance is why his story still resonates with 49ers fans. Smith was not simply a promising player who flashed for a few months. He was, for a brief window, one of the most disruptive defensive players in football.
His career, however, was repeatedly interrupted by arrests, suspensions and substance-abuse-related discipline. The 49ers released Smith in August 2015 after another DUI-related arrest. He later played for the Raiders and Cowboys and attempted a comeback with the Seahawks in 2021, but his time in Seattle ended before he played in a regular-season game.
Smith’s Later Work Added Another Layer to His Legacy
Smith’s later years included efforts to speak openly about the pressures that can come with professional sports. In 2024, he launched “I.M. Loading,” an initiative aimed at helping young athletes with mentorship and recovery coaching, according to ESPN.
That part of the story matters because Smith’s legacy cannot be reduced to either his sack total or his legal record. His NFL rise was extraordinary. His struggles were public. His final years included an attempt to turn those experiences into guidance for others.
For now, the most important fact is also the clearest one: Aldon Smith’s cause of death has not been released. His family’s decision to pursue CTE testing is a step toward answers, not a conclusion.
Erik Anderson is an award-winning sports journalist covering the NBA, MLB and NFL for Heavy.com. He also focuses on the trading card market. His work has appeared in nationally-recognized outlets including The New York Times, Associated Press , USA Today, and ESPN. More about Erik Anderson