Sean of "I Am Sam" (4)
I believe the answer is:
penn
'sean of i am sam' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for penn that I've seen before include "William --, founder of a US state" , "Milk actor" , "founder of colony" , "US state (abbrev.)" , "William ---, Quaker colonist" .)