Young and successful, he may be finished with pie (5)
I believe the answer is:
yuppy
'pie' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'young and successful he may be finished' is the wordplay.
I cannot quite understand how this works, but
'young' could be 'y' and 'y' is located in the answer.
'finished' could be 'up' (eg 'time's up' means the time is finished) and 'up' is located in the answer.
This explanation may well be incorrect...
'with' is the link.
Can you help me to learn more?
(Other definitions for yuppy that I've seen before include "Young well-paid city worker" , "affluent worker" , "Rich kid" , "Well-paid city professional; rhymes with young dog" .)