To some extent Peter Parker, Spiderman falls into this, at least in earlier stories. He has great skills and ambitions but he is not able to apply himself out of his responsibility as a superhero, as a family man and is often regarded skeptically by his friends for not always being there.
Walt in Gran Torino is a subversion. He's genuinely Bad Ass, and while his family doesn't pay him much attention or respect, the rest of his neighbourhood certainly does.
Another interpretation is that everyone knows Walt is a Jaded Washout except himself: His wife asked their priest to watch after him after her death because she knows that he has no connection to his sons. Everyone thinks he is an old crazy man. Only after Walt realizes his racism is a flimsy excuse to feel better at the expense of others can he be a hero.
Sonny Koufax (Adam Sandler) in Big Daddyappears to be heading in this direction, as at the beginning of the movie he's a law-school graduate who never took his bar exam and leads a semi-slacker lifestyle thanks to a cash settlement he received when a taxicab ran over his foot. He eventually does get his act together and is admitted to the bar.
Female example: Mavis Gary in Young Adult is a former Alpha Bitch prom queen who's now in her thirties, divorced, and ghostwrites teen-lit novels in order to recreate her high school Glory Days.
Jeeter Lester in Tobacco Road was once a respectable cotton farmer, but gradually fell into squalid, shiftless poverty.
Jack Malloy, from the MWC-inspired sitcom Unhappily Ever After. A used car salesman divorced from his wife and living with a rabbit doll that talks to him.
Pete Hornberger from 30 Rock is implied to be this at home. However, 30 Rock is a Work Com, not a Dom Com, so we never actually see Pete at home, and don't see much of his wife, either.
Due to the complaints of parents groups and his marriage to Rita Repulsa, by the end of the second season of Power Rangers this has happened to Lord Zedd of all people. Right down to his father-in-law's evil empire stated to be conquering Zedd's former territories in a throwaway line.
Ray Drecker from Hung became this without even realizing it.
Ben from My Family includes aspects of this - although not the "underpaid" part, being a dentist.
Howard Moon. Only without the "past glories" part. Any time he makes reference to any kind of former triumph, you get the distinct impression he's wildly exaggerating, or just lying outright.
Making Howard a bizarre combination of the Jaded Washout and Small Name, Big Ego, since he variates between thinking he's a smooth talking, artistic, dark and brooding genius, with understanding that he's utterly pathetic
Georg Bjarnfredarson from Naeturvaktin clings desperately to his memories of the happy young adult life he had in a Swedish leftist commune and routinely trots out his five university degrees as proof of his superiority. He is a sad middle-aged man with serious personality flaws that make him unemployable in anything above the most menial positions.
Jay Pritchett (no-so-incidentally played by Ed O'Neill) of Modern Family is an interesting subversion. He's very wealthy - and otherwise plays this trope straight-up. He often comes off as very jaded, constantly ignored and disrespected by his friends and family, or at least constantly worries about it (especially regarding his current wife), and in spite of his wealth feels he falls short of achieving his goals and recognition. He's also been shown on more than one occasion to overly rely on past glories (or attempt to revel in current glories, namely, again, his current wife). A lot of fans consider him either a more financially successful Expy or Alternate Character Interpretation of Al Bundy.
Robert Baratheon from Game of Thrones. The only part of his character that doesn't quite fit is the fact that he rules the Seven Kingdoms of Westeros.
Debbie, the protagonist of the song "1985" by SR-71 (later covered by Bowling for Soup), is a rare female example.
Her dreams went out the door When she turned twenty-four Only been with one man What happened to her plan?
Zero from The Adding Machine can't even boast of any past glories other than having worked twenty-five years at the same job without missing a single day. His ignorance, intolerance, and total lack of both imagination and achievement mark him as a failure of the first order.
The Nostalgia Chick knows she's a waste of space deep down. When Dark Nella is about to end her pitiful, nerdy, judgemental, shut-in existence, she's only really upset at being called nerdy.
The Nostalgia Critic had a year long Story Arc where he was getting more and more miserable about his job, involving bitching at other contributors for doing it better than him and trying to invade a country because he was desperate for some kind of power.
In some episodes of The Simpsons, Homer exhibits this trope - particularly in the spoof of the 49up series of documentaries, in which Homer was dissatisfied with his life in general. At other times, of course, Homer seems to invert this trope.
Simon Trent, the typecast actor who played the Gray Ghost, years after the show was cancelled, in Batman: The Animated Series. It's a more sympathetic portrayal than most, however, and he eventually does get out of his slump.
The Small Name, Big Ego page mentions a couple of high-school-jock types (Dash from Danny Phantom, and the Bradster from American Dragon Jake Long) who are actually prototypical Jaded Washouts— completely aware that, lacking any real redeeming features, these are their Glory Days, and they're keen to milk the time for all it's worth, before they flunk out of college and spend the rest of their lives pining for a time they spent making sure the unpopular kids would be too resentful to show up to the high school reunion.
The Venture Bros.: Rusty Venture was a Former Child Star, these days he's a bitter, cynical, pill-addicted has-been— thanks in no small part to his amazingly traumatic childhood.
Most every adult character on The Venture Bros qualifies to some degree. The creators have called the show their tribute to 'glorious failure.'