Winston delivered a share of the Big Ten title, and the rest of the conference took notice.
The junior on Monday afternoon became MSU's ninth Big Ten player of the year since the conference began giving the award in 1985.
"I think I've grown in a lot of ways. Just more confident, more aggressive," Winston said on BTN Live after the announcement. "I'm a better leader for my team. All of those type of things, I think I took a big step in. ... I think just really, my poise. I don't let the mistakes get to me, I don't let them take away from what I'm capable of.
"I've made a lot of mistakes throughout the years, and I just keep learning from them. That's really where the growth is."
A 6-foot-1 point guard from Detroit, Winston became the seventh to receive the honor in Tom Izzo's 24 seasons.
"Cassius' first year, I think half of the state was mad at me for how he was playing and where he was playing and what he's doing. There is a process to all of this," Izzo said Monday. "And when you go through the process and you come out on top, that's special for a coach, a family, a player. And it teaches him things he's gonna use for the rest of his life.
"And so I'm really proud of that for Cassius. It makes me feel good that it's OK to struggle a little bit early, what's important is are you getting better each and every day, each and every year? I think we'd all agree he's gotten better just about every day since he's been here and deserves the accolades he is getting and hopefully will continue to get."
Junior forward Nick Ward also earned third-team All-Big Ten honors by both the coaches and media. Sophomore forward Xavier Tillman earned the league's Sixth Man of the Year award. Senior guard Matt McQuaid landed on the conference defensive team of the year.
A unanimous All-Big Ten first-team pick, Winston ranks fourth in the Big Ten at 19.0 points and first with 7.6 assists per game this season heading into the postseason. Only Maurice Ager in 2005-06 (19.3 points) and Denzel Valentine in 2015-16 (19.2) have averaged more points in a season under Izzo. Winston has made 41.3 percent of his 3-pointers and is shooting 47.1 percent from the field and 82.6 percent at the free-throw line.
During conference play, Winston's 19.6 points were third and he led the league with 7.9 assists. He averaged 20.1 points in the final 18 conference games after the Spartans lost shooting guard Joshua Langford for the season, and Winston upped it to 21.2 points and 8.8 assists in the five games after Ward suffered a broken left hand against Ohio State on Feb. 17.
"He's just a different guy," Big Ten Network analyst Jon Crispin said of Winston. "Everything looks as if it's half-speed, but it's not without intensity, it's not without purpose. Everything Cassius Winston does is calculated. He's one of the most intelligent guys on the basketball court."
Winston joins Scott Skiles (1986), Shawn Respert (1995), Mateen Cleaves (1998, 1999), Morris Peterson (2000), Kalin Lucas (2009), Draymond Green (2012) and Valentine (2016) as Spartans to earn Big Ten Player of the Year honors. Winston is the sixth MSU point guard to win the award.
Winston also was named a first-team All-American by Sporting News on Monday morning.
Ward, who is expected to return for this week's Big Ten tournament, is averaging 15.1 points and 6.7 rebounds in 26 games. The 6-9 forward suffered a hairline fracture on his left hand during the Ohio State game on Feb. 17.
Tillman averages 9.3 points and 7.0 rebounds in all 31 games, 25 of them off the bench. The 6-8 forward stepped into the starting lineup with Ward injured and has averaged 14.4 points, 6.5 rebounds and 2.5 blocks in the past five games.
The Spartans (25-6, 16-4) open Big Ten tournament play at 12:30 p.m. Friday against the winner of Thursday's game between No. 8 Ohio State and No. 9 Indiana.
Purdue's Matt Painter was named Big Ten coach of the year over Izzo, while Boilermakers junior guard Carsen Edwards joined Winston as unanimous first-team selections. Michigan's Ignas Brazdeikis was named freshman of the year.