He is introduced in the first episode as a Chicago police officer with weight issues who attends a meeting of Overeaters Anonymous.
In Season 5, though, Mike finds out that Molly went back on birth control without telling him due to the pain and frustration of two years when she was unable to conceive a child, and they resolve to pursue avenues like adoption as they still love each other and want to raise kids.
She is very sweet, intelligent and caring, but she can be hypersensitive and has a very bad financial history thanks to a large amount of credit card debt.
It is later revealed in a session with a psychologist that Mike's stabilizing presence, something she hasn't had since her father died, has allowed Molly to finally feel comfortable taking risks.
Melissa McCarthy won the Primetime Emmy Award for Outstanding Lead Actress in a Comedy Series in 2011 for her portrayal of Molly Flynn.
Until the middle of Season 2, he did not have a steady girlfriend, and Mike has frequently alluded to Carl employing prostitutes or having one-night stands with strippers.
After a rather depressing break up with his girlfriend Christina (she leaves him for her ex-husband), he goes through a string of random women until towards the end of season 4, when he begins relationship with Molly's sister Victoria.
In an episode before the Season 5 finale, this relationship sours when Carl announces to Mike that he plans to propose to Victoria, only to change his mind.
Eventually they work out their differences, as both of them hate their new partners and Carl defends Mike when the other cops (including several hard-core macho officers whom they both dislike) make fun of him.
In the final episode, it's revealed that he and Victoria were secretly fooling around once again, but in a conversation with Peggy he admits that all of the old feelings were resurfacing, hinting that there's a possibility that they might become a couple again.
When Mike wondered aloud what made her change her mind, Victoria never mentions the discussion she had with her, knowing she got through to Peggy.
When shown doing her job, she treats the bodies she's tasked to do the makeup on with respect and even wishes one luck on his journey to the other side.
On that same episode, she has a conversation with Mike about death and what happens after one dies, and even explains her party attitude (she thinks it best to have as good a time as one can while alive in case there's no afterlife).
She is extremely hostile to him for a couple of days and after Molly arranges that they talk at a neutral location Joyce reveals that she was embarrassed and realized that she ran into 'an honest cop who was only doing his job'.
She frequently teases Mike for his size and eating habits, even though it is revealed in multiple conversations that her late husband was also a very large man.
He is a widower and tends to be chauvinistic and sarcastic, and also likes to openly discuss his sex life, one of the main reasons neither Mike nor Molly seek out his company nor spend more time around him than required.
He is a high school dropout and can come across as unintelligent, though the series has shown or mentioned he had made a lot of money in the past through his various enterprises (some of which may be a bit "shady").
Although Molly knew he was a widower, she didn't know that he was broke due to his having to take care of his late wife when she got sick and eventually died until he explained it to her.
When he explained how he stayed by her side and took care of her during her illness, Molly warmed up to Vince and even helped him cook a Thanksgiving dinner that he was forced to prepare on his own.
Her tendency to lie when the truth isn't kind to her connected with that job when she told Molly she had "retired"; she'd actually been fired for being impossible to work with.
Mike usually plays along with her revisionist history, but finally gets pushed too far in this case and tells Peggy she got fired because she is bitter, toxic and unlikable by anyone.
Her longtime courtship of a sweet-natured and unsuccessful fellow Catholic named Dennis ended badly when she finally decided she was ready for them to have sex, only to realize he'd suffered a heart attack and died.
Despite her obvious disdain for Jack, the two sleep together after Mike and Molly's wedding rehearsal, but Peggy dumps him immediately after.
Peggy reveals that she has always felt guilty for leaving her abusive home at an early age, while her mother was stuck with a drunken batterer for a husband.
Mike assures his mother that while he wouldn't move back home then or ever, he will still make sure she's part of her grandchild's life.
Harry (David Anthony Higgins) attends the same Overeaters Anonymous meetings as Mike and Molly and becomes their friend.
The two dated once, and while it is suggested that Victoria does so out of sympathy, they attended a few other events as friends and Harry has been visibly happy to spend time with her in any capacity.
In a twist of irony, Reginald VelJohnson had previously played Carl Winslow, a cop on another Chicago-set series, Family Matters.