Go where you’re celebrated, Williams told himself six months before Barcelona. So he chose to leave his wife, Kristin, and their three children in Austin in order to feed his impulses, as he so often does. He’ll spend as many as 300 nights a year on the road, checking in with his family sporadically. Friends describe this wandering lifestyle alternately as “irresponsible” and “just him.”

As the sun sets on day one at Spannabis, Williams has swapped contacts and scheduled meetings with a host of potential business partners. What’s obvious is that two green things are in abundance. Cannabis, sure, but also cash. “The way the industry is growing, it feels newer, and it feels fresh,” Williams says. “It’s like I have the chance to make a difference and be a superstar.”

He pauses, then repeats in a whisper, “Be a superstar again.”

he million-dollar party is under way at the Casa Llotja de Mar, a 14th-century palace near Barcelona’s waterfront. There’s a VIP room upstairs, beyond the risotto station and the paella station and the open bar, where DJ Felix da Housecat is spinning. Ornate tapestries hang beside gold chandeliers. Hired dancers in sequin headdresses gyrate next to revelers holding joints in one hand, drinks in the other.

The soiree is courtesy of Advanced Nutrients, a Canadian hydroponics company that sells products like fertilizer to marijuana growers. Tonight’s bash is also a continuation of Williams’s weed renaissance, his first strides into a marijuana industry that has never been more accepted. Or more profitable.

Laws, policies, attitudes—they all seem to be changing. In June 2015 the House of Representatives voted to slash the Drug Enforcement Agency’s budget, halving the allocation for cannabis eradication. President Obama has said that he believes marijuana to be no more dangerous than alcohol, while an Associated Press poll in March found that 61% of Americans favor cannabis legalization. In May, the House voted to allow doctors to recommend medicinal marijuana to veterans in the now 25 states (and Washington, D.C.) where it is legal. And last month, for the second time, the Senate Appropriations Committee voted 16–14 to permit marijuana businesses access to federal banks, which would remove a major operations hurdle for an industry that so far has worked almost entirely in cash. (This bill is being held up in the House.)

Bob Rosato

Those changes have ushered in both a gold rush and a green one. Marijuana Business Daily, in its annual report, forecast that the cannabis industry’s economic impact in the U.S. could reach $44 billion by 2020, which would represent a 687% increase from ’13. The website predicted retail sales of between $3.5 billion and $4.3 billion in ’16 in states in which marijuana is legal for medical or recreational use.

Williams appraised that shifting landscape—half the country having legalized medical marijuana; the celebrities, like Whoopi Goldberg and Snoop Dogg, who have created their own cannabis-based product lines—and decided he wanted in, for reasons both financial and altruistic. He figures he lost between $5 million and $10 million in salary and endorsements when his NFL career stalled out because of four failed drug tests (all, he says, for marijuana) between 2002 and ’06. He wants to make that back and then some.

WILLIAMS ESTIMATES THAT BETWEEN 60% AND 70% OF NFL PLAYERS SMOKE MARIJUANA, INCLUDING QUARTERBACKS HE PLAYED WITH AND SOME COACHES.

Williams is cofounding a cannabis-friendly gym in San Francisco, Power Plant Fitness and Wellness, where patrons will be able to smoke marijuana or ingest edibles, then work out, take yoga and meditation classes, undergo acupuncture, or get massages. His partner on that venture is the same man, Jim McAlpine, who created the 420 Games, a marijuana-themed series of 4.2-mile races on the West Coast in which Williams participated this year. Williams is also interested in someday opening a chain of sports-themed cannabis social clubs named 34’s, after his jersey number; creating marijuana-infused nutritional supplements (like breakfast bars) and healing products (like massage oils); and giving speeches as a cannabis activist. “That money can make what I lost seem tiny, like pennies,” he says, perhaps generously.

For now, Williams is early in his fact-finding phase. Before the trip to Barcelona he read The Cannabis Manifesto by Steve DeAngelo, who argues for legalization and details the history of cannabis as medicine. He scoured the online library at his alma mater, Texas (where he is four classes away from completing his undergraduate degree in psychology), to pour over marijuana research dating to the 1960s.

The Other Side Of Pot This chemical won’t get you high, but it could save your brain BSIP/UIG Via Getty Images

In May, Williams traveled to Portland for the Arcview Investor Forum, where he listened to cannabis-related pitches. He went as an investor, entertaining dozens of ideas for everything from genetic sequencing research to regenerative organic farming techniques. “To say that conference changed everything is an understatement,” he says. Now he wants to create what he imagines as an advocacy group for marijuana (and other issues) made up entirely of athletes. He even came up with a name: Professional Athletes for Change. Together they’ll argue for more research and acceptance.

Williams has also partnered with Weedmaps, a tech company whose app helps users locate medical dispensaries. Two friends, Doug Francis and Justin Hartfield, founded the outfit in 2008 after spending most of their mornings smoking and brainstorming company ideas. The company now has 240 employees, with offices throughout the U.S. and in Spain (and staff in France, England, Germany and the Netherlands). They’re headquartered in tech country, in Irvine, Calif., with a smoke room and a studio for filming promotional videos for a YouTube channel.

Williams’s deal with Weedmaps includes a stake in the business but remains otherwise open-ended. He’ll blog for them, make appearances, film TV spots and start dialogue, especially in the sports industry, alongside other athletes, both active and retired. Just as important, he’ll provide Weedmaps with a voice closer to the mainstream, someone associated with marijuana but, until now, outside the industry. “He captures the zeitgeist of both the athlete and the pot user,” says Marc Emery, a Canadian marijuana activist nicknamed the Prince of Pot.

Ronald Martinez/Getty Images

To that end Williams hopes to chip away at some old stoner stereotypes, diminishing notions that people who smoke marijuana lie on the couch all day watching TV, gorging on Cheetos. That was never Williams’s relationship with cannabis. He identifies more with what he calls “the archetype of the mystic,” and points to a favorite quote from 19th-century philosopher William James: “The sway of alcohol over mankind is unquestionably due to its power to stimulate the mystical faculties of human nature, usually crushed to earth by the cold facts and dry criticisms of the sober hour.”

Cannabis unlocks “the part of us that connects with something bigger,” Williams says. “It’s the part that’s active during dreams. You become not so attached to your own stuff. If you integrate that [approach], then addictions—alcoholism, food, porn; all these behaviors that plague society—we’ll start to change them. Those things are a side effect of a lack of integration. That’s how I use cannabis.”

The party ends, and Williams meets up outside the palace with his new teammates from Weedmaps. They’re headed to the rooftop bar at the W hotel. “This, Williams says to no one in particular, “is where I’m supposed to be.”