The head coach is backing his injured captain, who is under-fire over his choice of social activities and continued absence from the struggling side's first team
Kewell has made just one appearance for Melbourne Heart, sitting out three weeks of the season with a whiplash injury suffered in the Round 1 derby against his former side Melbourne Victory.
Due to finally return in the game at home to the Western Sydney Wanderers on Friday, the veteran forward has now been ruled out for at least two more weeks after rolling his ankle in training this week.
His cause has not been helped by the fact he chose to play golf as his team-mates suffered a 3-0 defeat away to Brisbane Roar last Sunday.
But when asked if he has doubted Kewell's determination to succeed during his return to Australian football, Aloisi was unequivocal.
"Not at all," the Heart coach said.
"If everyone sees how hard he works, on the pitch, off the pitch. If you were with me yesterday after training, talking to him and saw how upset he was, you wouldn't be questioning his desire at all.
"I haven't seen a player that upset with an injury for a long, long time. Harry was distraught because he wants to be out there, he wants to help the players, help the club. He was looking good in training, feeling great and that's what's even more frustrating for him."
Aloisi sought to diffuse the fallout from Kewell's poorly timed extracurricular activities, claiming he had given the 35-year-old his permission.
"If he asks me if it's ok to play golf and I give him the ok, then it's ok," he said.
"If you see the pressure he's under, with people making up stories about him. That's part of being Harry Kewell. He's a popular guy. He's one of the most famous footballers we've ever had in this country. He needs an outlet. He didn't play during his injury. On his day off he wanted to play golf and I allowed it."
The continued absence of Kewell has forced the Heart to experiment with different combinations in the final third, and Aloisi acknowledged the team have struggled at times without the skipper.
"It changes a little bit because the last few games we've put David Williams in the number 10 position and he's not a number 10," he said when asked about the team's approach to the Wanderers game.
"He (Williams) gives us something different to Harry - a lot more forward runs, he's quick. Harry will give us a lot more possession, slow the game down when he has to and quicken it up. And the players seem to lift when Harry's out there. In training they seem a lot more comfortable on the ball.
"It's just unlucky he's rolled his ankle."