One who seemingly did as much as possible excellently (7)
I believe the answer is:
maxwell
'one who seemingly did as much' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Maybe there's a link between them I don't understand?
'possible excellently' is the wordplay.
'possible' becomes 'max' (I can't explain this - if you can you should give a lot more credence to this answer).
'excellently' becomes 'we'll' (I've seen this in another clue).
'max'+'well'='MAXWELL'
'as' acts as a link.
Can you help me to learn more?
(Other definitions for maxwell that I've seen before include "Victorian scientist" , "Pioneer of electromagnetism - Czech-born tycoon" , "Robert, once a press baron" , "James Clerk --, Scottish physicist" , "Scottish scientist" .)