Dentons, one of the world's largest law firms, poached a senior partner from Jones Day to build a dedicated marijuana practice.

The partner, Eric P. Berlin, told Business Insider that he's "really looking to be the number one firm" in the cannabis industry.

Berlin worked on the four-way merger that became TILT last year, and was instrumental in crafting Illinois' medical marijuana law.

One of the world's largest law firms poached a senior partner to build out a dedicated marijuana practice, Business Insider has learned.

Eric P. Berlin, formerly a partner at Jones Day, joined Dentons in January as a partner in the Chicago office. As part of his new role, Berlin will spearhead the firm's work with cannabis industry clients, along with Kathryn Ashton, the chair of Dentons' healthcare practice, and Kelly Fair, a member of Dentons' litigation practice in San Francisco.

Read more: Big law firms are building out specialized pot practices to chase down a red-hot market for weed deals

"Dentons was interested in building what would be widely regarded as the number one practice for the more sophisticated clients in, or impacted by, the cannabis industry," Berlin told Business Insider in an interview. "There was a synergy there — I was interested in being able to do that."

Berlin said he knew Ashton from working with cannabis clients in the Chicago area. After a period of "courtship," Berlin said Dentons' sold him on building out the new practice group.

A tangled web of regulations

Berlin first started taking a serious look at marijuana after he read research that showed how patients suffering from myriad digestive issues — as well as multiple sclerosis — had used the drug for palliative relief.

As the president of the University of Chicago's GI Research Foundation, Berlin started to take on pro bono work to help craft Illinois' medical marijuana law roughly a decade ago.

After that legislation passed, he started to take on some clients who were applying for medical marijuana licenses. Starting in 2014, as Colorado legalized marijuana for adult use, Berlin said he "saw where the industry was going."

Read more: Marijuana companies are using a 'backdoor' strategy to tap the public markets — and it's fueling an M&A boom

"I knew there was going to be a building demand for sophisticated legal services, the kinds of normal legal services we to provide to all sorts of clients," Berlin said. And besides the business opportunity, he found the ever-shifting, tangled web of regulations around marijuana intellectually fascinating.

As part of his work at his former firm, Jones Day, Berlin worked on the four-way merger between Briteside Holdings, Sea Hunter Therapeutics, Santé Veritas Holdings, and Baker Technologies — which became TILT — a publicly traded company, among other M&A transactions.

He's also helped counsel clients both within, and impacted by, the marijuana industry, including the California-based vape company Hmbldt "work through the maze of federal uncertainty."

Sam Barber, president and CEO of the Cultivate dispensary, arranges smokable strains of cannabis before opening on the first day of legal recreational marijuana sales, Tuesday, Nov. 20, 2018, in Leicester, Mass. AP Photo/Steven Senne

Getting prepared 'well ahead of the market'

Berlin has big goals for his new role — even though, as he admits, he's still getting settled in.

"What we're forming is a truly comprehensive group, where we'll provide all the legal expertise that is needed in the industry globally," said Berlin. "We'll have the personnel in place to provide all of that."

He'll have his work cut out for him. A number of top law firms, including AmLaw 100 firms Duane Morris and Baker Botts, have established cannabis practices to chase down an opportunity that could hit $80 billion in the next decade, according to analysts from investment bank Cowen.

But what will set the new practice apart, said Berlin, is that it will be composed of lawyers with specific cannabis industry expertise.

"This is not cannabis criminal lawyers trying to become commercial lawyers. This isn't commercial lawyers who know nothing about the cannabis industry, trying to be cannabis lawyers. We have the expertise all the way around," said Berlin.

Read more: A cannabis CEO who led turnarounds at FAO Schwarz and Patagonia explains why he's looking to poach 'nimble' people from small companies — rather than big-name execs

On that note, Berlin said one his first tasks this year will be to do some hiring from outside the firm.

Berlin's location in Chicago could prove to be fruitful as well, as Illinois' new governor, J.B. Pritzker, has said marijuana legalization would be one of his top priorities for his first year in office.

"Right now there are very few firms that provide the really high-level counseling and transactional work cannabis companies need," Berlin said. "That's complicated, layered M&A, reverse takeovers into Canada, going public, and all the banking that has to do with that. We want to be able to provide all of that for our clients."

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