Around the stadium and the training ground, the French defender is an affable, enthusiastic presence; on the field, there can be a more aggressive, impulsive figure.
He was sent off against Brechin City on Saturday after kicking the ball away in frustration and receiving his second yellow card. It was also Mohsni's second dismissal this season, since he was shown a red card after the final whistle against Airdrieonians in December. On both occasions, manager Ally McCoist spoke of the need to remind Mohsni of his responsibilities to the team and to retain his self-discipline.
Yet Mohsni has a history of being hot-tempered. In three and a half seasons in British football, the defender has been shown 28 yellow cards and six reds.
During his spell at Southend United, there were even run-ins with team-mates as well as opponents, although Mohsni insisted last week that he has calmed down. The incident against Brechin was rash, but on other occasions he has reacted to goading from opposition supporters, always in a good natured way but betraying the fact that they had been affecting him.
Mohsni was aware of the magnitude of his mistake on Saturday and apologised to his team-mates. He cannot be a serial offender, though, because the goodwill would not then last. He is popular at Rangers, with colleagues and supporters, so the challenge is to find a balance between his competitive nature and some self-restraint.
"On Saturday, it was a daft red card and he made it hard for us towards the end of the game," said Nicky Clark, the Rangers striker. "Bilel knows that himself. But he's brilliant around the place, he's a lovely big guy. Every morning, he comes in and it's 'how you doing everyone?'
"Obviously, he's a bit different when he's playing. He's got a bit of hardness about him. I certainly wouldn't fancy having a fight with him. He's quite loud and vocal in the dressing-room. And it affected him after the game on Saturday. He was upset and angry with himself. He's a passionate guy and that showed what it meant to him."
On Friday, Dunfermline Athletic will travel to Ibrox in the Scottish Cup and the expectation is of a feisty occasion. Previous meetings this season have been full-blooded, and their last encounter at Ibrox was a physical contest, so the onus will be on Mohsni to not react. When Rangers won at East End Park in December, the scoreline was comprehensive at 4-0 but it was also a heightened atmosphere, one that the Rangers players responded to positively, although Mohsni did also react directly to some home fans.
"It's important that he keeps his head against Dunfermline in the cup on Friday night because it'll be a battle against them," said Clark. "It's vital that we keep everyone on the park. Every club, including Dunfermline, have tried to be physical with us. They think that's the best way to beat us but we'll take on that challenge. And we can give it out as well as take it. We want to be in the next round and hopefully I'll be back for the quarter-final.
"Bilel's just one of these players who has that streak in him. It's part of him and you don't really want to take it out of him. You need that in a player sometimes. He's a determined big guy who wants to do well. You wouldn't want to take it out of him.
"If I kick him [in training], I say sorry straight away. Bilel is a nice guy. You do get players [who] are a bit different on and off the park, but you need that. When I cross the white line, I change. You want to win, you want to do well and you'll do anything not to get beaten. It's fair to say Bilel changes."
Clark is currently injured, having fractured a bone in his foot, but he hopes to return to the first-team next month. The injury was likely exacerbated after Clark failed to realise how serious it was, playing on in the game that it occurred - against Airdrie last December - then being an unused substitute in the following match. Since he has been injured, Clark has had to watch Dean Shiels and David Templeton return to prominence and form, but he remains confident that he can return to the side once fit again.
"I will have a job trying to get back in the team but it's good to have that competition," added Clark, who was speaking at Murray Park yesterday to promote the inaugural Topps SPFL official sticker album.
"Hopefully I can get back soon and be involved in the games when we hopefully wrap up the title. The timing of [the injury] was frustrating because I was starting regularly and scoring goals. But I'll just need to bounce back and hopefully the boys keep winning."