Law student Joseph Frawley, 25, has pledged to sleep in his car for 15 weeks while he completes his honours thesis at the Australian National University (ANU) to support a program that enables homeless and other disadvantaged people to access higher education.

Mr Frawley, a former intern at the St Vincent de Paul Society, is raising awareness and funds for the society's Clemente higher education program.

He began Joe's Thesis Sleepout on a freezing night in the middle of July and plans to continue his campaign until the end of his thesis in October.

"It wasn't too frosty last night but the Canberra winter does bite," said Mr Frawley, speaking curled up in blankets on the lowered front seat of his small sedan.

"I've really tried to emulate what it would be like ... for someone forced to live in their car.

"So I'm not trying to kit it out with lots of heaters or anything like that.

"It's supposed to be a bit difficult."

The temperature has plummeted well below zero during Mr Frawley's campaign and the cramped conditions guarantee he never gets a full night's sleep.

"Minus five wasn't really a sleeping night for me, I was waking up every hour," Mr Frawley said.

"When I got into the car there was already frost on the inside of my windshield — so I knew I was in for a cold night."

Mr Frawley hopes to raise at least $13,000 for the Clemente program — that's $1 for each word of his thesis.

"When I [interned] at Vinnies I saw the massive problems that Vinnies are having to deal with," he said.

"So any way that I can help, I really think is important."

Frank Brassil, president of the St Vincent de Paul Society Canberra/Goulburn said the Clemente program, in partnership with the Australian Catholic University, enables people who have experienced homelessness, family breakdown, addictions, disabilities or mental health problems to have a university education.

"Joseph's selfless dedication to making a difference in the community and giving a hand-up to people less fortunate is incredibly humbling," Mr Brassil said.