The plea was made just before his trial was to start.
He will spend six months on probation on the charges and will be subject to random drug testing.
Margera, 44, was charged with assaulting his brother and making threats to other family members.
Bam MargeraGilbert Carrasquillo/GC Images
The incidents took place during a two-week visit last year.
At a hearing last year, Margera told the judge he was getting drug and alcohol treatment.
Margera acknowledged his prior condition outside the courthouse.
