Fellow loanee Arturo Lupoli drifted down the left wing and cut back for Jones to score from eight yards out and consolidate Derby's second-place spot.
Palace offered little first-half threat but were better after the break, with Tom Soares going close from 25 yards.
Giles Barnes nearly added a second late on before Darren Ward's close-range header almost stole a draw for Palace.
Derby manager Billy Davies:
"But the most important thing was that even through that sticky period we were well organised and showed determination.
"We will be going into January when the transfer window reopens with the intention of improving the squad."
Crystal Palace boss Peter Taylor:
"We started the game too slowly and I was disappointed with our first-half performance.
"We allowed Derby to play their football and whether we showed them too much respect I don't know, but in the second half the boys were a different class.
"We are not having a great deal of luck at the moment. I am not making excuses but we need something to drop for us.
"The second half was a lot more pleasing and, although we now had two defeats after a four-match unbeaten run, there have been a lot of positives to come from those defeats."
Derby: Bywater, Edworthy, Leacock, Moore, Boertien, Oakley (Malcolm 59), Jones, Seth Johnson (Michael Johnson 87), Barnes, Stead, Lupoli (Smith 71).
Subs Not Used: Peschisolido, Jackson.
Booked: Edworthy.
Goals: Jones 22.
Crystal Palace: Speroni, Lawrence, Ward, Hudson, Granville, Soares, Kennedy, Watson (Fletcher 46), McAnuff (Scowcroft 76), Morrison, Kuqi (Green 75).
Subs Not Used: Flinders, Borrowdale.
Booked: Granville, Watson.
Att: 23,875
Ref: J Moss (West Yorkshire).