The Democratic lawmaker from Minnesota recently became the fifth cosponsor of legislation to allow cannabis cultivators and sellers operating in accordance with state laws to be taxed just like any other business.
He also signed onto a bill that would allow those businesses to access financial services from banks.
Earlier this month, the former "Saturday Night Live" star was one of six senators to introduce a broad bipartisan bill that would amend federal laws so states can enact and implement their own medical cannabis laws without federal interference.
The leadership on marijuana issues is a far cry from when Franken said on a BuzzFeed podcast last year (in response to a question I submitted) that he was "not the guy to ask" about cannabis policy.
In his answer then, he did acknowledge that he should probably study up on the issue because the state he represents is one of more than two dozen that allows medical marijuana.
"I should know more," the senator said, jokingly adding, "or it's not important or somewhere in between."
A month later, Franken added his name to an earlier, now-expired version of the comprehensive medical marijuana bill that he is an original cosponsor of in the new 115th Congress. But he never did add his name to the 114th Congress's versions of the cannabis taxation and banking legislation.
Now, the senator is on a bit of a marijuana bill co-sponsorship spree, and some observers think it's good politics -- in addition to good policy -- at a time when Franken's name is being floated as a possible 2020 presidential candidate.
"With clear public support in favor of outright legalization, presidential aspirants now recognize that marijuana reform is something that can no longer be ignored," Justin Strekal of the National Organization for the Reform of Marijuana Laws (NORML) said in an interview.
A Quinnipiac University poll released in April found that 60% of U.S. voters -- and 72% of Democrats -- support legalizing marijuana.
When it comes to medical cannabis, 94% of all voters and 96% of Democrats are on board. Just 13% of Democrats and 21% of voters overall want the federal government to interfere with state marijuana laws.
Other potential Democratic presidential candidates such as fellow Sens. Cory Booker of New Jersey, Kirsten Gillibrand of New York and Elizabeth Warren of Massachusetts have increasingly taken on leadership roles in the fight for marijuana law reform.
Franken, who discussed his past marijuana, cocaine and LSD use in a book he published earlier this year, also joined four other senators in writing a July letter asking U.S. Attorney General Jeff Sessions not to go after state-legal industrial hemp growers.
But Strekal, of NORML, wants Franken to do even more, saying, until he "puts his name on a bill that outright deschedules cannabis from the Controlled Substances Act, I remain uninspired."
In July, Booker filed legislation to do just that, and more. And in the last Congress, Sen. Bernie Sanders of Vermont, a 2016 presidential candidate, filed cannabis descheduling legislation.