Famous old man following nation's leader (5)
I believe the answer is:
noted
'famous' is the definition.
(noted can mean well-known or famous)
'old man following nation's leader' is the wordplay.
'old' becomes 'o' (abbreviation).
'man' becomes 'ted' (Ted is a man's name).
'following' means one lot of letters go next to another.
'leader' suggests taking the first letters.
The initial letter of 'nation' is 'n'.
'o'+'ted'='oted'
'oted' put after 'n' is 'NOTED'.
(Other definitions for noted that I've seen before include "Remarkable" , "saw" , "Observed - recorded" , "Having renown" , "Made a record - celebrated" .)