Counter-terrorism police were called in after the incident at the University of Sydney on Tuesday, where the teen is accused of stabbing a 22-year-old man in the neck at the inner-city Camperdown campus about 8.30am.
The victim was rushed to to Royal Prince Alfred Hospital but was in a stable condition late on Tuesday.
Police ruled out religion as a motivating factor behind the attack, instead blaming the ability to access extreme violent content online as what allegedly radicalised the teen.
Counter-terrorism police and forensic investigators were called to the scene in Sydney. (Dan Himbrechts/AAP PHOTOS)
NSW Police Assistant Commissioner Mark Walton said the teen's ideology would likely be classed as "mixed and unclear", as he put it: "the salad bar of ideologies".
"A lot of these vulnerable people, they're not linked to one particular ideology, they will move as they're exposed to different things," he said on Tuesday.
"It might be of white supremacist neo-Nazi, it can easily flip into a religious ideation, it's a very complex environment that some of these vulnerable people are engaged in, not a linear position."
The 14-year-old was arrested after he attended the same hospital, where he was treated for cuts and undertook a mental health assessment.
He was known to police and government agencies, Mr Walton said.
A university spokeswoman said staff were working with authorities and there might be an increased security and police presence on campus while investigations continued.
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