PHILADELPHIA – These days, Mike Brey looks like a day trader who has endured a particularly aggressive happy hour. Notre Dame’s head coach has traded ski lodge chic for businessman-on-a-bender. He ditched trademark turtlenecks for open collars, unfastened buttons, slicked-back hair and slept-in-a-ditch stubble. He dresses like a lost soul on his fourth martini and down to his last Marlboro Light. He looks primed to view a Vegas sunrise. He looks, to be honest, kind of awesome.

“I love that,” Notre Dame point guard Matt Farrell said. “Who cares? Just let it ride.”

“I like the look,” forward Bonzie Colson said. “I think he’s the smoothest coach in the league.”

“I guess he’s past the midlife crisis,” longtime assistant Rod Balanis said, laughing.

When Brey leads sixth-seeded Notre Dame into Friday night’s regional semifinal at Wells Fargo Center, his sartorial choices will accurately represent both his team and his outlook. The Irish have become March staples, reaching the Elite Eight last season and nudging their way to at least the Sweet 16 this season. Brey, the former George Washington and DeMatha alum, has created a free-flowing offensive team he wants playing fast and loose. He has the casual attire and the gregarious personality to match.

“What you guys are seeing now, it seems like it really came about the last three years,” said former player Torrian Jones, now a Notre Dame radio analyst. “That’s always been coach. He was a young coach making his chops, so he was always reserved and somewhat conservative. I think now you see it more in his conversations and interviews.

“He doesn’t over-coach. We don’t run sets and stuff like that. We just free-flow, let it go. You train well to be skilled, and you make the right decision in the flow. That’s his personality. He’s just like smooth jazz. He lets it roll. He’s got his thing going now. His swagger is just increasing every single year: Here I am. I’m comfortable. I’m getting after it. My guys are loose.”

Every act Brey performs is designed to make his players relax, because that’s how he believes they will play their best. His current look is even more casual than a turtleneck, so sure, why not? He views stubble as good luck, so this season he decided to shave only on Sundays or at the first sign of a losing streak.

Before Notre Dame’s last-second win over Stephen F. Austin, he bragged to players about scoring his collegiate career-high at Northwestern State against Stephen F. Austin. After practice, he joins his players for games of knockout. “Hell of a free throw shooter,” Farrell said.

Brey has long been one of the most sociable coaches in college basketball, a trait that stretches back to before his career took off. Balanis, a Notre Dame assistant since Brey arrived in 2000, played at DeMatha when Brey, then in his mid-20s, served as one of Morgan Wootten’s assistants. The Stags traveled to tournaments, and Brey’s duties included proctoring tests on the road.

During one trip, Balanis had to take a history test under Brey’s supervision. While filling out answers in Brey’s hotel room, Balanis heard Brey shout, “Another illegal hit!” and slap Pete Strickland, a fellow assistant, on the back. Balanis looked up from his exam and realized Brey had been watching a Chicago Bears game and doing precisely zero test proctoring.

“He’s always been one of the funniest guys I’ve ever been around,” Balanis said.

Brey’s carefree nature creates comfort among players. Notre Dame notoriously plays a short rotation, but those who play know Brey will stand by them through mistakes. Brey invites players to his office just to talk, often about anything but basketball.

“It’s more than just being a coach,” Farrell said. “He wants to be our friend. He wants to know what’s going on.”

The connection allows Brey to reach players, and even chastise them, in deeper ways than many coaches. Coming into this season, he wanted fiery center Zach Auguste to harness his passion, which last year led to him breaking his hand punching a basket stanchion. Brey prepared film clips, from both games and practices, of Auguste showing bad body language after a bad play. The pair sat and studied them in his office.

“I was a type of an emotional player and sometimes I let it get the best of me,” Auguste said. “But over the course of the past few years I learned to channel it in a positive way and really use it to play my game at a high level.”

Brey’s loose approach manifests publicly in his rollicking personality. After Notre Dame beat Duke in the ACC tournament, Brey declared the Irish enjoyed “spoiling [stuff]” in the ACC, then chased after an associate and asked if he had a shot of Jameson to spare.

Of his team’s propensity for nail-biting finishes, Brey said: “We play the most exciting games in this tournament. I mean, we’re driving a heck of a lot of ratings. So CBS, they should send me a check when this damn thing’s over, as a matter of fact.”

Of new rules allowing underclassmen to declare for the draft and then return to school, Brey said: “It’s great for the young people. I don’t want to hear about, it’s tough on coaches. One of my assistants started whining about it. I almost fired him last night. I said, ‘Shut up.’ ”

Jones calls Brey “the king of one-liners.” He has come to believe they all have purpose. Thursday afternoon, the Irish walked off their bus and toward the arena for practice. Security checked bags, and the line stalled. From the back, Brey hollered, “Let me ask you guys something. Is this the way Springsteen comes in here? If this isn’t the entrance he uses, then I don’t want to use it.”

The players laughed. Rather than mulling how they would play for their season in another day, they were cracking up, again, at their scruffy coach.

“Something simple like that, it’s nothing,” Jones said. “But it’s everything, you know what I mean?”