The United States will legalize marijuana at a federal level in 2019, according to the chief executive of a leading company in the industry.

Kevin Murphy, of U.S.-based cannabis firm Acreage Holdings, said Thursday he believes that a key bill aimed at recognizing legalization of cannabis will be passed this year.

The STATES Act, a piece of bipartisan legislation proposed by Senators Cory Gardner and Elizabeth Warren, would allow businesses like Murphy's to operate legitimately, giving them access to bank accounts and letting them list on U.S. stock exchanges.

"I believe 2019 is going to be the year" of weed legalization in the U.S., Murphy told CNBC's Karen Tso at the World Economic Forum in Davos. "I believe that it's going to take place through the STATES Act."

"From our vantage point its very straightforward and we couldn't be more pleased to be leading as the largest player in the United States," he added.