The forward had been an alternate captain since he was acquired in a trade from the Ottawa Senators on Feb. 25, 2019.
"Honestly, I was just kind of speechless," Stone said. "For this organization in three years to be where it's at, it's very humbling for me. Big honor. Something that I'm not going to take lightly, and something that I'm really excited to do."
The Golden Knights, who entered the NHL as an expansion team for the 2017-18 season, did not have a captain for their first three seasons.
"We've made the decision in each of the three preceding years to go with alternate captains only, and this time around, in discussions that we had with president George McPhee, with (coach) Peter DeBoer, his coaching staff, myself, we felt we had the obvious guy and that this was the time to name a captain," Golden Knights general manager Kelly McCrimmon said. "You see the relationship he has with his teammates. As he's settled in here now, starting his third year here with the team, I think he's got a lot of respect."
Stone scored 17 points (seven goals, 10 assists) in 20 Stanley Cup Playoff games after not playing the final six regular-season games last season because of a lower-body injury. He scored 63 points (21 goals, 42 assists) in 65 games last season and was the runner-up to Ryan O'Reilly of the St. Louis Blues in voting for the 2019 Selke Trophy, awarded to the top defensive forward in the NHL.
"I think he's a guy that does it right every single day, how he approaches the game, how he approaches practice, how he approaches and is with his teammates," DeBoer said. "I also love the emotion that he displays on the ice. He's invested in the game, and you can tell that every shift. I've never seen a guy happier when other guys on the team score than Mark Stone. He's happier than when he scores himself. So that selflessness shines through. He's got all those qualities you're looking for."
Stone, who has seven seasons remaining on an eight-year, $76 million contract ($9.5 million average annual value) he signed with Vegas on March 8, 2019, has scored 74 points (26 goals, 48 assists) in 83 games with the Golden Knights in two seasons and 29 points (13 goals, 16 assists) in 27 playoff games.
"I don't know exactly how it's going to go, but I don't think I'm going to change a ton," Stone said. "I'm an emotional player, very passionate about the game, and ultimately my main goal is to win the Stanley Cup, and I'm going to for sure be preaching that to everybody. This is an organization that wants to win and wants to win now, and we've got to have everybody who's part of this organization committed to winning and being the top team at the end of the season."
Alex Pietrangelo, who was captain of the St. Louis Blues for the past four seasons, and Reilly Smith were named alternate captains.
Selected by Ottawa with in the sixth round (No. 178) of the 2010 NHL Draft, Stone has scored 385 points (149 goals, 236 assists) in 449 regular-season games, and 42 points (18 goals, 24 assists) in 54 playoff games.
"He does everything the right way on the ice in terms of what the coaches ask of him, so certainly he leads by example in that regard, and I think he cares about his teammates," McCrimmon said. "He's got a lot of really good leadership traits, in my opinion, and the best captains, it happens naturally. The best captains continue to be themselves. That's why Mark is our captain. That's why he was selected, and I expect that he'll grow into this role very nicely. And in fact, I think him being named captain will help him be an even better player."
Two NHL teams remain without a captain: the New York Rangers and Ottawa Senators.
NHL.com columnist Nicholas J. Cotsonika contributed to this report
