Parker's donation was reported in Proposition 19 campaign finance filings this week.
And he's not the first big Proposition 19 donor with ties to the social networking site. Facebook co-founder Dustin Moskovitz has given $70,000.
Neither Parker nor Moskovitz are still with the Palo Alto-based company, but both still have ownership stakes. "The Social Network," the film chronicling the contentious origins of Facebook, was No. 1 at the box office last week.
The only other six-figure donation to the pro-pot campaign - also $100,000 - came from adult entertainment entrepreneur Phil Harvey.