Well, to make a long story short, Craig Newmark is Jewish!
Since Craig Newmark's mother is Jewish, and in Orthodox Judaism and Conservative Judaism, those with a Jewish mother (or those who underwent a halakhic conversion) are considered Jewish, then that makes him Jewish. His father is Jewish too.
Craig Newmark was born on December 6, 1952 in Morristown, New Jersey, United States.
He is best known for being the founder of the San Francisco-based international website Craigslist.
If you see any details that require update, please Let us know!