Use ultimately effective ruse to frame Mike (6)
I believe the answer is:
employ
'use' is the definition.
(synonyms)
'ultimately effective ruse to frame mike' is the wordplay.
'ultimately' suggests the final letters.
'ruse' becomes 'ploy' (both can mean a trick or scheme).
'to frame' indicates putting letters inside.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
The final letter of 'effective' is 'e'.
'e'+'ploy'='eploy'
'eploy' placed around 'm' is 'EMPLOY'.
(Other definitions for employ that I've seen before include "Keep (someone) occupied" , "Use or take on" , "Occupy" , "Take on - recruit" , "Give job to (someone)" .)