Smith pleaded no contest as charged on Wednesday to three felony counts of illegal possession of an assault weapon and to two misdemeanor counts of driving under the influence of alcohol, the Santa Clara County District Attorney's office confirmed in a statement.
Smith is scheduled for a July 25 sentencing in Santa Clara. He could be sentenced to anywhere between no time in custody to four years and four months in jail. The no contest plea sets up the NFL to impose potential discipline for Smith.
"We are aware that Aldon entered a plea today in a case that we have closely monitored," 49ers general manager Trent Baalke said in a statement. "Today was an important step towards bringing that situation to a resolution. Any further questions concerning today's hearing should be directed to his attorney."