He turned the situation into an Atlantic Division championship and the team's first playoff appearance since 2008, which was more than enough to convince general manager Masai Ujiri that the right man for the job was already in house.
Casey received a three-year contract extension on Monday, a person with knowledge of the deal told The Associated Press. The person requested anonymity because the team has not announced the move.
The agreement came one day after the Raptors lost Game 7 of their Eastern Conference playoff series to Brooklyn when Nets star Paul Pierce blocked a potential game-winning shot by Toronto point guard Kyle Lowry in the closing seconds. The fast resolution addressed one of the team's biggest question marks heading into the off-season.
"He's a great dude," guard DeMar DeRozan said of Casey before news of the contract went public. "Sometimes you don't even look at him as a coach because you can talk to him about any situation. I think that helped us a lot."
Casey was in the final year of his contract when Ujiri was lured away from the Denver Nuggets. An executive typically likes to hire his own coach, and Casey was brought on in 2011 by former basketball boss Bryan Colangelo.
The Raptors won 23 games in Casey's first season and 34 in his second, and Ujiri immediately started making roster moves to address the team's troublesome salary-cap situation and start positioning it for greater flexibility moving forward. The most notable move was sending Rudy Gay to Sacramento, but Casey and his new-look staff took the hand they were dealt and turned the Raptors into one of the most surprising teams in the league.
"This guy did so much and really got us ready," guard Greivis Vasquez said. "As a leader, you've got to give him a lot of credit. He did a great job. I thought we got better throughout the season. We gradually got better and the coaching staff was great."
Toronto went 48-34 to win the division for just the second time in franchise history. The Raptors also came close to advancing to the second round of the playoffs for just the second time in franchise history.
"We were right there," Casey said after Game 7.
Casey helped Lowry, a talented guard with a reputation for being a handful for coaches behind the scenes, harness his ultra-competitive nature and mature into the kind of reliable leader that the team needed.
The 28-year-old Lowry delivered the best season of his career and ingratiated himself with the Raptors' passionate fan base to set up what should be a lucrative trip through free agency this summer.
Casey also helped DeRozan blossom into a more well-rounded player. DeRozan averaged a career-high 22.7 points, but his 4.0 assists were also well above his previous career high of 2.5.
"He's not going to tell you do to something just to do it," DeRozan said. "There's a reason behind everything. Once you respect a man's word like that, you're going to work for him."
It also has to be comforting for Casey, who was told by Ujiri that he would get every opportunity to be the coach for the long term if he put the work in and helped the team improve like it did. Ujiri backed up his word, which should sweeten the experience for Casey after his first head coaching job went so sourly in Minnesota.
The Timberwolves gave Casey just a season and a half before firing him with a 20-20 record in 2007. Things only went south from there for the Timberwolves, and Casey went to Dallas to win an NBA title with the Mavericks as an assistant before getting another shot.
In Toronto, unlike in Minnesota, Casey will get the chance to finish what he started.
AP freelance writer Ian Harrison in Toronto contributed to this report.Suggest a correction