Senator King has been outspoken in his support for legalization in his state and federally. 

Supports federal legalization. https://bowdoinorient.com/2018/11/02/studzinski-debates-highlight-differences-turn-testy/

Secure and Fair Enforcement Regulation (SAFER) Banking Act

S.179 - VA Medicinal Cannabis Research Act of 2019

S.1200 - Secure And Fair Enforcement Banking Act of 2019

H.R.1595 - SAFE Banking Act of 2019

S. 683 CARERS Act of 2015 (2015-16)

In a statement of support for the SAFER Banking act, Senator King said, “A business that follows all state laws should be able to access the banking system – that’s pretty commonsense.” 

In response to Session's attack on marijuana
"Independent U.S. Sen. Angus King of Maine issued a statement saying that each state should have the ability to implement policy that reflects its citizens' wishes. Other members of the delegation could not immediately be reached for comment."
1/4/18
http://mainepublic.org/post/how-attorney-general-s-decision-tighten-federal-marijuana-policy-affects-maine

"Senator King believes the decision to legalize marijuana on a federal level for recreational purposes is significant and must be thought through carefully and comprehensively," spokesman Scott Ogden said in an email. "He is interested to see the effects of legalization in places like Colorado and Washington, as data emerges that will better inform the decision-making process on this issue."
1/21/14
http://www.pressherald.com/2014/01/21/push_to_legalize_marijuana_likely_in_more_maine_communities_/

“We owe it to our veterans who need medical assistance to do everything we can to help them face their challenges in healthy, productive ways, including research into alternative treatments that may help ease their pain,” King said in a statement about the legislation. “Maine’s veterans have earned nothing less than our complete support, and we must explore every possible avenue to help them.”

In 2016, he joined a bipartisan group of senators by signing onto a letter asking the U.S. Treasury Department’s Financial Crimes Enforcement Network to clarify guidance for banks that deal with cannabis businesses.

9/27/18 https://www.marijuanamoment.net/heres-where-maines-us-senate-candidates-stand-on-marijuana/

Website: https://www.king.senate.gov/

Email: swoodworth@angusformaine.com

Web: https://angusformaine.com/

Phone: 202-224-5344