Freddie is somewhat of a nerd; he takes his schoolwork very seriously and is the technology "buff" of the show.
He is somewhat strict with Carly, to prove himself a responsible guardian after meeting their grandfather in i Wanna Stay with Spencer.
Throughout most of season two, they appear to have developed a tolerance for each other, with a genuine friendship developing late into the season (although they still maintain antagonistic attitudes towards each other).
Freddie also became Sam's first kiss, just so they could get it over with. He lives with his domineering and overprotective mother in the apartment across the hall from Carly and Spencer's.
Despite his usually eccentric demeanor, he is not fooled easily, and his intuition is surprisingly accurate.
He works as a sculptor and artist, a common plot device on i Carly, and much of his work can be seen in their apartment.
By the second season, they had developed at minimum a tolerance for each other, and by the end of that season developed a genuine friendship (although still maintaining antagonistic attitudes towards each other out of habit).