Tareq Kamleh was attending a Thornlie mosque just weeks before joining Islamic State in Syria and claimed to have given up drinking and womanising for his faith.
A former schoolmate of the Perth doctor turned IS recruit has also recalled how the 29-year-old would defend Islamic extremism, even after the September 11 attacks.
Members of the local Muslim community said they were surprised by Dr Kamleh's appearance in an IS recruitment video, having seen him at the mosque as recently as last month.
Dr Kamleh is understood to have told people he had been accepted for work with aid agency Doctors Without Borders.
One man who has known Dr Kamleh since he was a child said he was intelligent and a good Muslim.
The man said he had never seen a bad side to Dr Kamleh, who grew up in Perth and attended Al-Hidayah Islamic School in Bentley and Lynwood Senior High School.
A local imam said young people at the Thornlie mosque were told to reject the principles of IS.
A former colleague who worked with him at Princess Margaret Hospital last year said Dr Kamleh spoke about reconnecting with his faith.
"Early last year we were in the after-hours GP side of PMH and there were no patients," the PMH health professional said, speaking on condition of anonymity.
"I was going through my notes and he was talking quite vocally to this other doctor.
"It was about how he used to drink and be a womaniser and how he has reconnected with Islam, and that now he finds his life so much better.
"I found the whole conversation inappropriate. He didn't say anything extreme but it was more about how he made his life better."
He had no complaints about Dr Kamleh as a doctor, describing him as "respectful and non-judgmental".
Dr Kamleh worked at PMH for about six months and also worked at Mount Hospital.
He also studied and worked in other Australian States and former work colleagues in Queensland described him as someone who liked to party and could not understand his sudden strict adherence to Islam.
But one former schoolmate of Dr Kamleh, who said he spent five years with him at Lynwood SHS, said his appearance in the IS video came as no surprise.
"He showed glimpses of radicalisation, especially around the time of September 11," the former student told 6PR radio.
"He would make off-the-cuff comments about how they deserved it.
"He never said anything about fighting for Islam but he was supportive of anything they did."