Well that reminds me. Allan Sherman is The Painless Dentist.
An undercover FBI agent staking out a Prohibition Era speakeasy:
Long Cool Woman In A Black Dress by The Hollies.
Saturday night I was downtown
Working for the FBI
Sittin’ in a nest of bad men
Whiskey bottles piling high.
A hired gun with twenty notches on his pistol, who’s ready to quit the business:
Running Gun by Marty Robbins.
I rode out of Kansas City, going south to Mexico
I was running dodging danger,left the girl that I loved so
Far behind lay Kansas City and the past that I had earned
Twenty notches on my six gun marked the lessons I had learned.
Many times I sold my fast gun for a place to lay my head
Till the nights began to haunt me by the men that I left dead
Couldn’t stand it any longer with the life that I’d begun
So I said good-bye to Jeannie and became a running gun.
An Arizona Ranger takes out an outlaw with twenty notches on his pistol.
Could it be that same hired gun who fled from Kansas City?
Big Iron by Marty Robbins.
Now the stranger started talking made it plain to folks around
Was an Arizona ranger wouldn’t be too long in town
He came here to take an outlaw back alive or maybe dead
And he said it didn’t matter he was after Texas Red
After Texas Red
No, it appears that the outlaw taken down by the Arizona Ranger isn’t the same outlaw who left Kansas City, even though they both had twenty notches. The Running Gun shoot-out takes place in Amarillo, while the Arizona Ranger did his business with his big iron in Agua Fria.
Rocket From the Crypt - Ditch
The Breeders - When I Was a Painter
Going back to the Dylan well, “Lily, Rosemary and the Jack of Hearts” has a lot of occupations:
Cabaret dancers
Actors
Bank robbers (is that an occupation? It pays well)
Diamond mine owner
Backstage manager
Hangin’ judge
Another dentist: Dr. Longjohn 
Bruce Springsteen, in “Dancing in the Dark,” says “I’m tired of sitting around here trying to write this book.” Could be his literal occupation, or a figurative observation about his life in general.
Is this the same “Dark Lady” was messing around with Cher’s beau?
Fortune Teller was a staple for British bands of the sixties, a song with a surprising outcome. Here’s the Who’s version from Live At Leeds.
Speaking of trucker songs, I just realized no one has mentioned “Eastbound and Down” yet, which is yet another song about truck driving.
And more Weird Al: The main character in “Biggest Ball of Twine in Minnesota” works at Big Roy’s Heating And Plumbing. His exact job isn’t specified but I think we can safely assume he’s either a plumber or HVAC repair technician.
Still more Weird Al: in “I Lost on Jeopardy!” the other players are a plumber and an architect.
Frank Zappa’s Willie the Pimp is a pimp.
The narrator of Montana is planning to grow dental floss on his ranch and become a dental floss tycoon, and also raise some bees, but not for the honey.
Even more Weird Al
She Never Told Me She Was A Mime
Skipper Dan-Actor and amusement park jungle tour guide
Party In The CIA Agent
Apologies if this has already been posted: “Rocket Man” by Elton John is about an astronaut. I guess. (“It’s just my job five days a week…”)
“I’ll Wait” by Van Halen is about a model that David Lee Roth was dating at the time.
Are you for real
It’s so hard to tell
From just a magazine
Yeah, you just smile and the picture sells…
That reminded me of the J. Geils Band’s “Centerfold”.
More early Bowie - Uncle Arthur was a shopkeeper.
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Pete Townshend’s Keep On Working
Talking Heads - Don’t Worry About the Government
Oh, how about “Working Man”, by Rush?
In that vein, John Lennon’s Working Class Hero.
Steely Dan’s eponymous Cousin Dupree “kicked around a lot since high school, I’ve worked a lot of nowhere gigs From keyboard man in a rock’n ska band to haulin’ boss crude in the big rigs.”
And in “Everything Must Go” they’re all going out of business although it’s not specified who has what job aside from “Dave in Acquisitions.” Also by Steely Dan.
Can’t remember if Rod Stewart’s
Steal my daddy’s cue and make a livin from playin pool. (“Maggie Mae”)
has been mentioned yet.