"Change is good, you know?" comedian Jim Jefferies announces early in his new FX series "Legit," which debuts tomorrow night at 10:30. "Can't keep going on like this. I think I'd like to have kids."

Jim sounds sincere as he explains this to his friend Steve (Dan Bakkedahl), but quickly adds that he doesn't want to get married — that, in an ideal world, he would meet a woman, get her pregnant, and she would stick around long enough to get the baby through the sleepless nights/dirty diaper phase before conveniently dying.

"That would really be best for everyone," he explains to a horrified Steve, who tries to work around his friend's narcissism by suggesting, "My therapist says if you want to get out of your head, you do something nice for someone else."

"Legit" is the story of a selfish pig who decides to do something nice for someone else, but it's not a fairy tale. Jim does the right things, but inevitably for the wrong reasons, and always with a twisted logic that makes it hard to see any of his actions as entirely generous.

Steve, you see, has a younger brother named Billy (DJ Qualls) with a severe case of muscular dystrophy. He's confined to a motorized wheelchair and is capable of very limited movement: he can manipulate a computer mouse, but needs you to put his hand on it, and his only way to "leave the room" if he's mad at you is to turn his head. Jim likes Billy but finds the nursing home he lives in too depressing to visit. But Steve drags Jim along one day, and Billy sees in Jim an opportunity to get out of the home, visit a brothel, and finally lose his virginity.

Before Billy can even finish the request, an enthusiastic Jim interrupts to say, "Yes! I was put on Earth to make this happen!"

This is "Legit" in sick, funny microcosm. Jim really does want to help Billy, but he's also excited by the very idea of being part of such an event, and begins recognizing that there are advantages to being publicly associated with a disabled friend. When Steve learns that his parents were told about the excursion by Jim, Jim boasts, "I've been telling everyone!"

Jim and Steve not only take Billy to a whorehouse, but eventually liberate him from the home altogether and install him in their apartment, hoping to give him the kind of fun life that his condition has largely deprived him of for 32 years — and if Jim gets some fringe benefits out of the deal (like being able to check out the women Billy video chats with), then so much the better.

In addition to playing a fictionalized version of himself, Jefferies is also a writer and executive producer on "Legit" (along with Peter O'Fallon and Rick Cleveland), and the show feels very tonally similar to FX's "Wilfred" — and not just because fellow Australians Jefferies and Jason Gann could pass for brothers. Both are comedies in the sense that they're a half-hour long and at times capable of explosive, raunchy humor, but they're more interested in watching their main characters learn how to be men. There are good jokes (particularly in the premiere, the first of three episodes I've seen), but the show is dominated by an unexpected feeling of warmth and generosity. Jim really does want to help Billy, and to be a better person, even if his intentions are always undercut by his approach and ego.

Jefferies, a more popular comic in real life than he is on the show, has a cocky, scruffy appeal — imagine Ricky Gervais as a David Brent who was sometimes capable of being as charming as he thought he was — and he works well with Bakkedahl and Qualls. And Billy is a great role for Qualls, who's been bouncing around showbiz since "Road Trip," an odd duck Hollywood never knows quite what to do with, even though everyone knows they want to do something with him. Jim is the protagonist, but Billy is more than just his charity project. He has needs and desires and flaws, and he really does like Jim beyond seeing him as a useful tool.

By design, "Legit" isn't as consistently funny as some other FX comedies like "It's Always Sunny in Philadelphia," but it nicely occupies that border between comedy and drama that have become home to both "Wilfred" and "Louie." It's a charming series that feels like it has a lot of potential for growth, and not just because its main character has nowhere to go but up.

Alan Sepinwall may be reached at sepinwall@hitfix.com