The correct answer is Walt Disney, but tangentially. The Mickey Mouse clock used Mickey's hands as clock hands, which seems to be the first example I can find when using Mickey's hand as an indicator:
Unknown image source
As far as I can tell, the pointing hand cursor originated as a PC cursor on HyperCard as mentioned in Bart's response, and was adopted for use on the web almost from the beginning as Mark Griffiths points out:
HyperCard was a big influence on some of Tim Berners-Lee's teams in Cern, and many of the hypermedia conventions he established were taken to Mosaic.
I am struggling to corroborate that statement. He continues saying:
If the pointing hand cursor had never existed, then a lot of design assumptions might not have been transferred from the HyperCard "link" to HTML and we could have anticipated the many years of work done to classify web accessibility for machines. and the whole spectrum of human beings.
However, the open / grip hand cursor is much older and was designed by Susan Kare (who made most of the icons for the original Mac). MacPaint (on the original Macintosh from 1984) used it as the "pan" icon:
That icon was modified slightly in the course of the classic System / MacOS to add things like a countdown wait animation:
Image credit: Bjørn Sortland, Ka of Isis.
The old point-and-click adventure games also used a lot of hand icons, often gloved with a rich design, which starts to point in that direction. Final Fantasy is a famous example. I think it's likely that there's an old point-and-click adventure game somewhere, possibly even one from Mickey Mouse, that used a cartoon glove like this long before it became part of the operating system, but I could not find none. explicit examples (it is not a genre about which I am particularly informed).
As far as I can tell, it was the pointer icon that first received the Mickey Mouse darts on the back of a computer, what happened in the Macintosh system software some time before Mac OS 9 (unfortunately I can not find more A specific example more than this, but it would not have been much earlier, since the pointing icon only became a system icon in Mac OS 8.5, this coincides with the launch of the Platinum user interface in Mac OS 8.5, which was all about a richer bitmap, graphics throughout the operating system):
Image credit: Nonme85851, DeviantART
The icons were aligned at some point, but it is not clear when:
Image credit: Off-screen graphics Worlds, images, cursors and icons Chapter 13 (PDF link)
It seems that the stylized hand icon was reverted to the original version of Susan Kare on OS X to Mac OS X 10.7.3 (when the two cursors were redrawn for the Retina displays and aligned stylistically):
Credit of image: Mark Edwards, Twitter
I took a look at the metadata for those cursors in OS X and it seems that they do not have any author credit specified (but it does say that they were working on Adobe Illustrator CS4 from April 17, 2008 at least until April 15, 2008 ). September 2011).