Mike Eastern is a private investigator.
"Mike Eastern, private Investigator. All varied aspects of crime and domestic issues considered. 24/7 service is guaranteed!"
That is how his business card reads. Eastern has plied his trade for a large number of years. Exactly how many is unknown but he talks early on about how he has had his office and often sleeping quarters above the Italian fast food joint for over eight years so it is certainly that long and likely longer. To get to his office you have to climb some stairs but more importantly to Eastern, so does he and he really does not like stairs.
He really does not like most things. He gets annoyed easily. He tends to bark and snarl and let those who are doing the annoying know that he is annoyed. Few people gets spared his sharp tongue. That likely helps explain the fact that he has been married three times already though it does not explain why the ex'es said yes in the first place. Eastern explains his lack of marital success on his allergy to wedding cakes.
Eastern was born Marcus Enstien. When he was old enough to need to make a living, he did so as a boxer and was fairly good at it until five years into this profession, an eye injury forced him out. That lead him to other trades where his fisticuffs would prove useful such "as a doorman or a bouncer, graduating to a security guard in a casino".
Having no desire whatsoever to do anything more than what he has been doing to make a living, such as that living is, Eastern was not looking to get involved in the spy business. He hardly seems to really want to be in the private eye business sometimes. But life dumps him solidly in a mess where the guys in grey coats were playing and he barely got out alive the first time. That, unfortunately, kind of means he is a survivor so when trouble happens again...
Oh, we never really know who these spy guys work for. "Spooks" is what the agency is named though that likely is what Eastern calls it. It is run by Commander Rogon with whom Eastern has a very strange relationship. Rogon seems to like Eastern but then he is in the deception business. Eastern seems to always be one straw away from anger with Rogon but that straw stays off the camel's back so no harm yet. It is an interesting situation.