On January 28, 2012, Aldon Smith was arrested for driving under the influence in Miami Beach, Florida.
On June 30, 2012, Smith was believed to have suffered stab wounds when attempting to break up a fight at a party at his residence. Two other people were shot in the incident. On October 9, 2013, Smith was charged with "three felony counts of illegal possession of an assault weapon" relating to the stabbing incident. The charges were later reduced to misdemeanors.
On September 20, 2013, Smith was involved in a single vehicle accident in San Jose, California. He was subsequently arrested on suspicion of driving under the influence and possession of marijuana. After the loss to the Indianapolis Colts in the third week of the football season, he voluntarily entered a rehabilitation facility, to be put onto the non-football injury list with an indefinite leave of absence.
On April 13, 2014, Smith was detained and arrested following an incident at the Los Angeles International Airport in which Smith became belligerent and uncooperative with a TSA agent, who alleged Smith claimed he was carrying a bomb. After interviews revealed that Smith did not clearly state he was carrying a bomb, the Los Angeles City Attorney decided to drop the charges. Smith was suspended for 9 games for the 2014 season.
On August 6, 2015, he was arrested in Santa Clara, California, for an alleged hit and run after driving under the influence, and vandalism charges. He was released by the 49ers the following day August 7, 2015, as a result