Abdel-Kader Russell-Boumzar, 17, said he wished to apologise to "the bloke on the train" and "everyone that was offended by my video" as he left the Brisbane Magistrates Court after being granted bail on Monday.
Lighting a cigarette, the apprentice mechanic told reporters he felt "very bad" and didn't mean to post the video online, before getting into a waiting car.
He and his 18-year-old friend Bailey Clout surrendered to police on Sunday after Clout's video of the vile October 2 incident went viral and sparked a furious reaction, including death threats against the pair.
The footage allegedly showed a drunk Russell-Boumzar spitting on guard Josphat Mkhwananzi and hurling racial abuse at him after Mr Mkhwananzi asked one of the teenagers to remove their feet from a train seat on the Ipswich line.
Russell-Boumzar is banned from Queensland trains and can't go out without parental supervision under strict bail conditions imposed by the unimpressed magistrate who heard the case.
Clout, who laughed hysterically while filming the abusive tirade, was fined $400 after pleading guilty to creating a public disturbance.
Magistrate Bronwyn Springer slammed the alleged attack as "disgusting behaviour" before imposing the strict bail conditions on Russell-Boumzar.
"He's 17. He's still carrying on like a child so he can be treated like one," she told the court.
Russell-Boumzar didn't enter a plea to charges of assault, assault occasioning bodily harm, making threats, creating a disturbance and using a carriage service to menace.
The assault occasioning bodily harm charge was later upgraded to serious assault so a forensic medical officer could test Russell-Boumzar's blood.
He faces a possible jail sentence and must live with his parents or grandparents.
He must also abide by a curfew, report to police three times a week and is forbidden from going near any Queensland Rail infrastructure.
Lawyer Tim Clements said the teen would be contesting the spitting charge, despite apparent video footage of the act.
Police Commissioner Ian Stewart and Queensland Transport Minister Scott Emerson on Monday praised Mr Mkhwananzi for his calm demeanour under attack.
Mr Emerson said he spoke to the guard to pay tribute to his restraint.
"This behaviour is never acceptable and the fact that the community is so outraged by it really shows that we are a tolerant community," he told reporters.
"But even in any tolerant community there will always be some idiot out there."
Russell-Boumzar's case was adjourned to November 3.
OTHER RECENT RACIST RANTS ON AUSTRALIAN PUBLIC TRANSPORT
* Sept 2014: Muslim woman's head is slammed into a train carriage and she is racially abused on a Melbourne train
* Aug 2014: An Aboriginal woman launches a racist attack on an Asian woman on a Perth train
* July 2014: Sydney woman Sue Wilkins is filmed verbally abusing an Asian train passenger, saying: "Why did you come to this country? This is our country" and pulling her eyes to appear slanted.
* April 2014: Woman calls an African man a "black c***" on a Melbourne train
* April 2014: Musician Kym Purling is spat on and abused in an unprovoked racist attack on an Adelaide bus
* Feb 2014: Two women are filmed abusing a 77-year-old visually impaired passenger on a Gold Coast bus, saying: "Oh bro we're in Abo land". The man himself later said he was not indigenous.
* April 2013: A man yells at two Korean people on a Sydney bus about the Japanese bombing of Australia during World War II and calls them "f***ing bastards".
* November 2011: Two men racially abuse a French woman on a Melbourne bus, telling her to "speak English or die" and threatening to cut her with a box-cutter.
