That comfort was only reinforced over the next 10 weeks on the ice and in the dressing room.
It left Kane with an easy choice as he headed toward free agency, and he bypassed a chance at the open market Thursday by signing a seven-year deal worth $49 million to stay with the Sharks for the long term.
"It's good to be wanted and I wanted them just as much as they wanted me," Kane said. "The fact that we were able to work out a deal so quickly reflects that. Obviously, when you're a free agent you have the option to do what you want, and I made it clear to them that I didn't want to go anywhere else."
Kane will be paid $9 million the first year of the deal, followed by salaries of $8 million, $6 million, $7 million, $7 million and two years at $6 million, according to a person familiar with the deal who spoke on condition of anonymity because terms were not released. He also has a limited no-trade clause.
Kane, who turns 27 in August, was acquired from Buffalo at the trade deadline in February and became a key part of San Jose's team down the stretch and in the playoffs.
Under the terms of that trade, the Sabres will get a first-round pick in 2019 instead of a second-rounder because Kane signed with San Jose. The selection is lottery-protected, so it could be moved to 2020.
The Sharks aren't concerned about that price.
"You don't find guys like this unless you're picking in the top three, four guys in the draft, and no one wants to be there," coach Peter DeBoer said. "When you're signing free agents, especially elite players and guys that are going to play huge roles for you, you really want to know about them as much as possible. And you really don't know a player until you stand behind the bench and are around them every day. So that was a nice luxury to have. I think we all felt comfortable that this was a guy that could help us win."
Kane's status was one of the biggest questions heading into this offseason for the Sharks, who were knocked out of the playoffs in six games in the second round against eventual Western Conference champion Vegas.
Thornton is the other prominent potential free agent on the team, but he's said he's willing to come back on a reduced one-year deal.
The Sharks still have salary-cap flexibility to make more moves, which will be easier now that Kane's deal is done and he can be slotted in on a top line.
"He plays with great speed and fits with not only our game but where the league is trending," general manager Doug Wilson said. "To get him in place and secured was very important to us. Top-six forwards like that, there aren't many out there, and when you get one you want to make sure that he's secured. It fills in our roster."
Kane stepped right onto the top line with captain Joe Pavelski after arriving in San Jose and helped ease the loss of Thornton, who went down with a season-ending knee injury in January. Kane used speed and physical play to deliver nine goals and five assists in 17 games and helped San Jose make the playoffs, giving him his first taste of the postseason.
Kane shined in the first round with three goals and an assist during a sweep against Anaheim. But he struggled a bit against the Golden Knights, slowed by injuries to his knee and shoulder that lingered from the end of the regular season.
He had one goal and a minus-5 rating in five games against Vegas. He missed Game 2 of that series when he was suspended for cross-checking Pierre-Edouard Bellemare.
Kane finished last season with 29 goals and 25 assists, his second-most productive season to his 30-goal, 27-assist campaign for the Jets in 2011-12. Kane has 186 goals and 168 assists in 574 career games since entering the NHL as the fourth overall pick by Atlanta in 2009.
Despite his credentials, there was not a robust trade market for Kane back in February, in part because he had issues off the ice and with some teammates during his stints with Winnipeg and Buffalo.
Kane also had legal run-ins.
In March 2016, prosecutors announced after a three-month investigation that Kane would not face a sexual assault charge. In June 2016, he was arrested for allegedly grabbing three women by the hair and neck during an altercation at a Buffalo bar. The charges were eventually dismissed as part of a plea agreement on the condition that Kane stayed out of trouble.
Also that year, the Sabres suspended Kane for one game for missing practice a day after pictures surfaced on social media of the player celebrating in Toronto after attending the NBA All-Star Game.
There haven't been issues in his brief time with the Sharks.
"We really started things off on the right note and it just carried on from there," Kane said. "The one thing about this team and this group and this organization is that they allow you to be yourself. They embrace you for that. It's a very unselfish group that makes it super easy to come into and mesh well with."