"Reid embodies what the Vegas Golden Knights stand for," general manager George McPhee said. "He's talented, he's a man of character and he never gives up.
"This was just a matter of being able to get a deal done with a young man we've been following for a year, and when it was done, we were ready to announce it. We're delighted he's actually the first guy. He embodies everything that we want in hockey players and sets a great example for all the other young men who are going to sign."
Duke (6-foot, 192 pounds) was a sixth-round pick (No. 169) of the Minnesota Wild in the 2014 NHL Draft but never signed with them. He skated with the New York Rangers at the Traverse City Prospects Tournament in Michigan in September, and also attended development camp with the Montreal Canadiens.
He has 250 points (113 goals, 137 assists) in 306 WHL games with Lethbridge and Brandon.
"It's tough, coming in as a free agent, because things are much harder sometimes that way," Duke said. "But looking at it now, it was such a blessing in disguise for everything to work out as it has here in the last little while. I'm so thankful for the opportunity that Vegas has given me and excited to move forward with them."