"It went swiftly. I got some weed over the counter," Sinclair told ABC News when reached by phone. "It's about time. I've been waiting for this for 50 years."
About a year after Michigan residents voted to allow the sale of recreational pot, hundreds of people lined up outside six dispensaries in the state to purchase weed for the first time without having to have a doctor's prescription.
Michigan became the ninth state in the nation, along with Washington, D.C., to allow people 21 and over to purchase recreational marijuana over the counter. In Vermont, weed is legal to possess, but not to sell.
"It's a good idea," Sinclair told ABC News.
John Lennon and Yoko Ono famously held a freedom rally in December 1971 pushing for Sinclair's release. Bob Seger and Stevie Wonder also performed at the concert and Jerry Rubin and Allen Ginsberg were among those who voiced support for the Flint native at the rally. Sinclair, who once managed seminal rock band MC5, was released soon after the event despite his 10-year sentence.
For the historic transaction, Sinclair purchased 10 joints prerolled with a strain of cannabis dubbed "Gorilla Glue No. 4."
Asked if he noticed any difference between smoking a perfectly legal spliff compared to the old illegal kind, Sinclair said no.
"It's smoking a joint," said Sinclair, who celebrated by lighting up while attending a poetry reading.
Sinclair made the purchase at 9:49 a.m. at Arbors Wellness, a dispensary in Ann Arbor.
Four of the six dispensaries licensed to sell recreational weed are in Ann Arbor. But according to the state's Marijuana Regulatory Agency, another 30 locations throughout the state are awaiting approval to sell recreational cannabis.
Not every town in Michigan has jumped into the marijuana marketplace. More than 400 cities in the state have rejected businesses that want to supply adult recreational weed, according to the Detroit Free Press.
Illinois is the next state up to allow the dispensaries to sell recreational weed beginning Jan. 1.
Unlike other states, where citizens voted to allow adults to legally purchase cannabis for recreational use, Illinois' legal weed law was passed by the state legislature in May and signed into law by the governor a month later.
"As the first state in the nation to fully legalize adult-use cannabis through the legislative process, Illinois exemplifies the best of democracy: a bipartisan and deep commitment to better the lives of all of our people," Illinois Gov. JB Pritzker, a Democrat, said in a statement after he signed the bill on June 25.
Other states where recreational marijuana is being legally sold include Alaska, California, Colorado, Maine, Massachusetts, Nevada, Oregon and Washington. Vermont natives can possess up to 1 ounce of marijuana and grow two mature plants or four immature plants.