Miami-Dade County jail records show Smith was booked Saturday morning and held on $1,000 bond. Jail records did not show whether Smith was represented by an attorney.
A Miami-Dade County Corrections spokeswoman said Smith was arrested by Miami Beach police. A police spokesman said he had no information immediately available about the arrest.
Smith was drafted as the seventh overall draft pick in 2011. During his first season, he had 14 sacks, a franchise record for a rookie linebacker. He also ranked first in the NFL in sacks among rookies.
The 49ers said in a statement Saturday that they were aware of the arrest.
"We take these issues very seriously, but will reserve further comment at this time, as this is an ongoing legal matter," the team said. "The 49ers will continue to gather the facts and monitor the developments closely."