<Li> Samuel `` Sam '' Anders ( Sean O'Neal ) -- Clarissa 's best friend and confidant . Generally more optimistic and upbeat than she is , he often asks `` What 's the worst that can happen ? '' He is perhaps best known for entering her second - story bedroom with a ladder after a distinctive guitar chord plays followed by Clarissa 's `` Hi , Sam '' greeting . He is smart and polite and enjoys skateboarding . His parents are divorced ( mentioned in the pilot ) . </Li>
who played sam in clarissa explains it all
Sean O'Neal