Mark puts his heart into roles with energy (12)
I believe the answer is:
characterise
'mark' is the definition.
('mark'->'characterize' is in my internal thesaurus and 'ize'->'ise')
'his heart into roles with energy' is the wordplay.
I cannot really understand how this works, but
'heart' could be 'h' (card game abbreviation) and 'h' is found in the answer.
'energy' could be 'ac' (AC is an example) and 'ac' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'puts' is the link.
Can you help me to learn more?
(Other definitions for characterise that I've seen before include "Typify" , "Be a distinctive feature of" , "Describe" .)