Worked out commitment daily at first (8)
I believe the answer is:
resolved
'worked out' is the definition.
(resolve can mean to work something out)
'commitment daily at first' is the wordplay.
'commitment' becomes 'resolve' (resolve can mean commitment or determination).
'at first' says to take the initial letters.
The first letter of 'daily' is 'd'.
'resolve'+'d'='RESOLVED'
(Other definitions for resolved that I've seen before include "Settled, found a solution" , "Firmly determined" , "tackled crossword again?" , "Decided firmly on a course of action" , "Settled conclusively" .)