Gil has so many jobs, it's difficult to even think about. Each episode he seems to have an even worse and more pathetic job than the last. I've linked to the episode guide where you can read more about it. :)
Job 1
Red Blazer Realty
Episode: 5F06
This is Gil's first job, and his longest job as well. He worked at Red Blazer Realty, selling houses. He has been working there for over twenty years of his life. His main project was to sell the "Whitman Place" but he failed miserably. A younger man named Nick Callohan had sold the house much more rapidly.
Gil was barely holding onto his job, because he was never able to close a deal. He must have sold a house at one point, because he had his very own cubicle. After Marge sold the "Murder House", she was given one of the walls of his cubicle.
Gil wasn't really comfortable working there, as he feared some of his co-workers, especially Cookie Kwan.
Job 2
Goodie New Shoes
Episode: 5F10
Look, a new job already, only four episodes after the last. He is now a shoe saleman, who apparently downn't know very much about shoes. Marge asks for a good, stiff, all-purpose dress shoe. Something for church, but also for doctors appointments, dental checkups, piano recitals, building dedications, visiting elderly relatives, haircuts, and shoe shopping...Amazing, isn't it? Gil offers them a brown shoe.
Gil seems highly uninterested in this job. He gives Lissa the store sock, and he ends up having to tie Bart's shoes for him, even though he has a bad back. "Hey, if you didn't want to you shouldn't have become a shoe salesman." Bart explains.
Job 3
Used Car Salesman
Episode: 5F18
Gil now works in a used car lot. He hasn't earned much money lately, and it's proven because he lives in the Hot Air Balloon in the lot. He has made an expensive purchase, a hot plate. But it's the usual bad luck. Homer and Marge steal the balloon, and the hot plate falls from it. Poor Gil...
Job 4
Computer Salesman
Episode: AABF03
Gil sells a Coleco computer system to the school. GO GIL! HE MADE A SALE! Whoooo! *coughs* "How many can I put ya' down for, a lot? Please say «a lot!» I need this."
Lisa controls Gils fate! He sounds worried: "And let's not forget ol' Gil, huh?" Gil almost loses the deal when saying that Coleco systems will rust. "Aw, thank God! Now, let's talk rust-proofing. These Colecos'll rust up on ya' like that, er ... shut up, Gil. Close the deal ... close the deal!"
Job 5
Used Car Salesman
Episode: AABF10
Gil has returned to the field of selling cars, and he nearly sells a Canyonero to Homer. When he is just closing up the deal to sell it, a co-worker Stan comes to "take it from there".
Gil: "Well, if you, well ... really? Wow, Hot, hot dog! A sale!"
Stan: "I'll take it from here, Gil."
Gil: "No, wait, no. Aw, you can't take my sale. My wife's going to leave me if I don't start bringing in the green. Come on, let me have this one, Stan, I'm begging you. Look at me, I'm begging you, Stan."
Stan: "Mmmm-hm" (he walks into his office with Homer) "Let's go write this up, shall we?"
Gil calling his wife on a rotary cell phone: "Honey, you should have seen me with my last customer, I ... no, but I came so close. This guy was as ... Whose voice is that? Is that Fred? ... Aw, you said it was over ... No, don't put him on -- Hello, Fred, h-hi."
Gil, Gil, Gil...
Job 6
Señor Ding-Dong's Doorbell Fiesta Salesman
Episode: AABF13
Gil works in the DoorBell store, and is having a rough time. Nelson has left a bag by one of the demonstration doors.
Job 7
Kwik-E-Mart
Episode: BABF03
In the ever so cool convienience store, Majula's water breaks. She and Apu rush to the hospital, but not before Apu says over the intercom "Clean up on Isle Three". Gil is working his way to the top? Hmm
Job 8
Amway Dealer
Episode: BABF14
Gil goes to an AA meeting, and pretends to be an alcoholic so he can talk to people about this product:
Gil:
Well, after I lost my third job in two days, old Gil was in a pit of despair.
Lindsey:
And that's when you realized you were an alcoholic?
Gil:
Oh, no, I never touch the stuff. But you don't have to be drunk to know the value of Amway. *everyone gasps* Now, this is used crankcase oil, which you ladies know is murder to clean up, you know. *he spills it on the floor* And company's coming...
Two men come in and carry Gil out of the room. "Aw, you're doing this at the worst possible time. Ow, you're finger's in my eye!"