Intrusion of popular Head of Art accepted by staff (6)
I believe the answer is:
inroad
'intrusion' is the definition.
(inroad is a kind of intrusion)
'popular head of art accepted by staff' is the wordplay.
'popular' becomes 'in'.
'head of' says to take the initial letters.
'accepted by' indicates putting letters inside.
'staff' becomes 'rod' (both can mean a stick or cane).
The first letter of 'art' is 'a'.
'a' inserted inside 'rod' is 'road'.
'in'+'road'='INROAD'
'of' is the link.
(Other definitions for inroad that I've seen before include "Incursion, raid" , "Sudden attack made into a country" , "One's intrusive" , "Encroachment, intrusion" , "Offensive" .)