Both were in court today; Lucan, with his hair tied back, listening to the hearing.
The school's lawyer Richard Harrison told the court Lucan was sent to Mr Melloy's office by a teacher who thought his hair was too long.
Mr Melloy asked Lucan to cut his hair, but the student refused and asked the principal to contact his father.
"Straight away you've got a refusal of the principal's request," Mr Harrison said.
"We've got continual disobedience."
His defiance of the rules was "harmful and dangerous" because it could influence other pupils who could think Lucan's actions were cool, Mr Harrison said.
There would not have to be evidence of anarchy or social disorder for Lucan to be suspended, because the principal would need to be ahead of that, he said.
Justice David Collins asked why Mr Melloy did not look at other disciplinary measures such as stopping Lucan from playing for the 1st XV or giving him detention.
Mr Harrison said because Mr Melloy was told by Lucan, in the presence of his parents, he would not comply, other disciplinary options were not open to him.
Lucan's lawyer Jol Bates told the court Lucan followed in the footsteps of human rights defenders including Martin Luther King Jr and Kate Shepherd, who challenged authority on a justified basis.
The school's rule around hair length was that it needed to be off the collar and out of the student's eyes.
Lucan would wear his hair tied up, off the collar and out of his eyes, so was therefore abiding by the policy and should not have been suspended, Mr Bates said.
"We're not splitting hairs."
Lucan had been at the Catholic school for three years with the same hairstyle, Mr Bates said.
Lucan had curly hair, which if cut, would become "boofy and turned into an afro", he said.
"He's simply not comfortable [with that]."
His hair was not a health and safety issue, nor was it a distraction to other students, he said.
Earlier this year, Lucan received a bravery award for for helping to save two women from drowning off a Napier beach in January last year. He was also in the school's 1st XV rugby team, Mr Bates said.
Neither of those factors were taken into account when Lucan was suspended, he said.
The case is continuing.