The 36-year-old centre, who spent the 2010-11 season in Montreal, was claimed off waivers by the Canadiens from the New York Rangers on the weekend. He had his first practice on Monday.
"When you get on that plane or, like me, you drive up, you feel by yourself," said Halpern. "It's an isolated feeling.
"But to be able to walk into a room and see Brian Gionta, Travis Moen, Josh Gorges, P.K. Subban — these are all guys I've kept in touch with — they're good smiles to see. These are guys I enjoyed playing with. You want to do well for those guys because they're good friends and teammates."
Halpern had only one assist in 30 games in New York, but was picked up by Montreal for his penalty killing skills and to add veteran depth heading into the final 17 games of the regular season.
The fourth line he skated on with Moen and Gabriel Dumont faces a particularly tough week.
The Canadiens (20-6-5) will try to end the Penguins' 12-game winning streak Tuesday in Pittsburgh, then face the archrival Bruins in Boston on Wednesday night before returning home to face the Rangers on Saturday.
The Canadiens are coming off a 2-1 defeat to Buffalo on Saturday that ended a seven-game points streak. They have not lost twice in a row in regulation time this season.
They hope Halpern can bring his strong faceoff and defensive skills to a team that has been sub-par in both areas, although Dumont has been their best on the dots in seven games since he was called up from AHL Hamilton with a 63.4 per cent success rate.
Montreal ranks 18th in the 30-team league in penalty killing at 80.0 per cent, although their ninth-ranked power play at 21.2 per cent gives them a respectable overall special teams score of 101.2. A total of 100 is considered good.
The Rangers may have felt Halpern was expendable because their penalty killing dropped from one of the league's best in 2011-12 to 12th at 82.1 per cent. But New York has had more trouble with a 25th-ranked power play, scoring on only 14.6 per cent of its chances for a 96.7 total.
Placing Halpern on waivers likely had more to do with clearing space for a move ahead of the April 3 NHL trading deadline. It put New York at 48 players under contract, two fewer than the maximum allowed.
"One of the bigger things was the number of contracts," said Halpern. "It looks like they're ready to make a move and there are certain things they needed to move around.
"They had a lot of injuries, especially on the fourth line, with Aaron Asham (who is ready to return) and Darryl Powe. But it was good group there, a good team. I was trying to make as big an impact as possible in a limited amount of time."
Montreal is likely still looking for a bigger, physical forward at the deadline, but Halpern fit their need for veteran depth up front.
"When you're in the last stretch of the season you need depth and that's why we claimed him," said coach Michel Therrien.
As they did in trading for winger Michael Ryder in late February, the Canadiens brought back a player who had been on the team before, knew the city and was used to the high-powered Bell Centre atmosphere.
"To come back to a place I enjoyed so much is a good pick-me-up," Halpern said.
His old colleagues are glad to have him back. Halpern was a popular player among teammates and fans two seasons ago when he had 11 goals and 26 points in 72 games. He returned to his first club, the Washington Capitals, as a free agent after that season and then signed with New York last summer.
"He's a great guy," said Subban. "When Halpy was here he got a chance to sit down and talk to my dad a bit, so my dad was pretty fired up when we brought him back.
"He's a good veteran. He'll be an important guy down the stretch."
It will be the second time this season Montreal plays back-to-back games against Pittsburgh and Boston. The last time, they lost in overtime at home to Pittsburgh on March 2, then won 4-3 at Boston one night later.
It will be Therrien's first game in Pittsburgh since he was fired by the Penguins during the 2008-09 season, just before they won the Stanley Cup under coach Dan Bylsma.
"It will be special," said Therrien. "I had some great moments there and I'm still in touch with some people. I have good memories of my time there."
Forward Brandon Prust skated separately with assistant coach Pierre Groulx and did some bumping to test his shoulder injury. He won't make the road trip but hopes to be back soon.
"He didn't progress as we'd hoped," Therrien said of Bourque. "That's the frustrating part of a concussion. You don't know (how long it will take to recover)."