The lowly worker — being released, he'd plod on (6)
I believe the answer is:
trudge
'plod on' is the definition.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for trudge that I've seen before include "Walk heavily or laboriously" , "March joylessly" , "tramp" , "Walk with slow, heavy steps" , "Plod doggedly" .)