Green’s Dictionary of Slang

johnny-on-the-spot n.

also Johnny-on-the-job, Johnny-on-the-place, Johnnie-on-the-spot
[johnny n.1 (1) + SE spot; note NY Sun Apr. 1896: ‘A “Johnny on the spot” is a man or youth who may be relied upon to be at a certain stated place when wanted and on whose assured appearance confident expectation may be based. It is not sufficient that an alert and trustworthy individual, to be thought deserving of the name “Johnny on the spot,” should restrict his beneficent activity to the matter of being at a certain place when needed. He must, in addition, render such service and attend to such business when there as the occasion may require, and such a “Johnny” must be on the spot not merely to attend to the business of others, but also to look after his own. Hence an individual who is prompt and farseeing, alive to his own interests and keenly sensible of means for promoting his own advantage is a “Johnny on the spot”.’]

1. (US) a reliable, punctual or decisive person or thing.

Penny Press (Minneapolis, MN) 21 Dec. 1/3: [heading] Pay up or Quit Firemen Who Are Not Johnny on the Spot Must Go.
[US]Ade Artie (1963) 19: I could see that a Johnny-on-the-spot, with a big badge, marked ‘Committee,’ was tryin’ to keep cases on her.
[US]Times Dispatch (Richmond, VA) 30 Apr. 10/3: One can see the boss Shanghai, who neither toils nor spins nor scratches for sustenance, but is Johnny-on-the-spot when some other rooster [...] unearths a worm.
[US]W.M. Raine Bucky O’Connor (1910) 106: When they want it, every one of these memoranda must be Johnny-on-the-spot before they can dig up the mazuma.
[US]A. Berkman Prison Memoirs of an Anarchist (1926) 191: I’m Johnny-on-the-spot to serve the cause, all right [...] and the cause is Me.
H. Hershfield Abie the Agent 8 Dec. [synd. cartoon strip] Any time you want a ‘sample ride’ in mine 1915 ‘Complex’ I’ll be Johnny on the place’.
[US]J. Black You Can’t Win (2000) 175: Those two kings of the First Ward were ‘Johnnie-on-the-spot’ and never allowed any of ‘their people’ to languish in the ‘can’ overnight.
[US]O. Strange Sudden 148: Useful fella that – reg’lar johnny-on-the-spot, ain’t he?
[Aus]E. Curry Hysterical Hist. of Aus. 27: Some fit and proper person should be there, by jingo, sort of Johnny on the spot, eh, what?
[US]W.R. Burnett Vanity Row 217: ‘Where’s Emmett?’ ‘Don’t know. Didn’t come in this morning. Didn’t call either.’ ‘That’s damn funny. Old Johnny-on-the-job. Maybe the poor slob’s sick’.
[US]The Treniers 🎵 Friend you go out in a hall / Want the joint to rock, / All you do is give us a call / We’ll be johnny on the spot.
[US] ‘Old Zebra Dun’ in G. Logsdon Whorehouse Bells Were Ringing (1995) 81: When the herd stampeded he was Johnnie on the spot, / He could mill a thousand longhorns as easy as you could turn a pot.
[US](con. 1949) G. Pelecanos Big Blowdown (1999) 303: ‘You’re right on time,’ said Burke. ‘That’s me [,...] Johnny-on-the-Spot.’.
Webb Jr & Lamb Secrets of Your Rising Sign 51: When the crap hits the fan, they’re Johnny-on-the-spot, a cool head in the face of danger.
[US]S. King Finders Keepers (2016) 148: Madden is going to be johnny-on-the-spot, and that’s lovely. Hodges is an on-time man himself.

2. attrib. use of sense 1.

[US]S. Ford Shorty McCabe 30: Out jumps a Johnny-on-the-spot citizen and gives him the low tackle.
[US]L. Block ‘You Can’t Lose’ in One Night Stands (2008) 197: My man came on with the johnny–on–the–spot pitch.

3. (Aus./US) one who is present, a witness, e.g. a news reporter.

[US]‘Digg Mee’ ‘Observation Post’ in N.Y. Age 19 Oct. 10/6: The Grace Baptist Church entertained ambitions of bringing Ben Anderson up on charges because he was ‘Johnny-on-the-spot’ with the stories of the ex-reverend.
[Aus]C. Hammer Silver [ebook] ‘You back on news?’ ‘Johnny-on-the-spot, just like you’.

4. (US) a portable latrine.

[US]H. Crews Feast of Snakes 17: This year, though, they had the Johnny-on-the-spots. Chemical shitters.