Smith's work as a leader is progressing rapidly (7,5)

'progressing rapidly' is the definition.
'forging ahead' can be an answer for 'progressing' (forging ahead is a kind of progressing). I am unsure of the 'rapidly' bit.

'smith's work as a leader' is the wordplay.
I cannot really see how this works, but
'as' could be 'in' (I've seen this in other clues) and 'in' is found within the answer.
'a' is found in the answer.
'leader' could be 'head' (head is a kind of leader) and 'head' is located in the answer.
This explanation may well be incorrect...

'is' is the link.

Can you help me to learn more?