Etymology
The Dictionary of American Slang suspects the phrase to have originated among California movie and show-business people as a reference to child clients of summer camps.
Noun
happy camper (plural happy campers)
- (chiefly US, informal) One who is thoroughly content or satisfied.
- Synonym: happy bunny
I will be a happy camper when they fix the potholes on my commute.
1989 April 26, Shirley Marlow, “Quayle Visits Samoa, Decides He'll Give It a Break”, in Los Angeles Times:“You all look like happy campers to me,” Dan Quayle to the people of American Samoa.
1997, Roz Denny Fox, Sweet Tibby Mack, page 132:"Call, but you can't fight union regulations" / "You're probably right. Still, their boss needs to know I'm not a happy camper."
2008, Deepa Kumar, quoting Ron Carey, Outside the Box: Corporate Media, Globalization, and the UPS Strike, Appendix, page 194:I had kept telling people that this company would be looking for a victim to pay for this. They would not let it go. And it wasn't just them—look at all the Mob guys I threw out of the union. They weren't happy campers.
- Used other than figuratively or idiomatically: see happy, camper.
References
- Christine Ammer (2013) “happy camper”, in American Heritage Dictionary of Idioms, second edition, Houghton Mifflin Harcourt, →ISBN, page 197.
- Eric Partridge (2005) “happy camper”, in Tom Dalzell and Terry Victor, editors, The New Partridge Dictionary of Slang and Unconventional English, volume 1 (A–I), London, New York, N.Y.: Routledge, →ISBN, page 961.
- “happy camper n.”, in Green’s Dictionary of Slang, Jonathon Green, 2016–present