Paper's previous boss went on and on (6)
I believe the answer is:
lasted
'went on and on' is the definition.
(to last is to endure or go on)
I can't explain the rest of the clue.
(Other definitions for lasted that I've seen before include "Endured, survived" , "Continued, being salted" , "Kept going" , "Continued for some time, endured" , "Persisted, endured" .)