He uplifts Smith's heart (3)
I believe the answer is:
tim
'he' is the definition.
'uplifts smith's heart' is the wordplay.
'uplifts' shows that the letters should be reversed in order.
'heart' means to look at the middle letters.
The centre of 'smith' is 'mit'.
'mit' written backwards gives 'TIM'.
(Other definitions for tim that I've seen before include "Tiny . . . is a lovable small boy from Dickens" , "- Rice, musical lyricist" , "Little fellow" , "Sir -- Rice, lyricist" , "Tiny . . . is a loveable boy in fiction" .)