The 32-year-old Californian man, who has spent time in Wellington, was the victim of a random attack last week after alighting a night-time tram at Preston.
Surgeons have had to extract excess blood from his brain, seal his fractured skull with metal plates and he will be left with a scar covering half his head.
The ukulele and trumpet player's jaw was broken and had to be screwed back into place, and nerves in his jaw were also damaged.
Despite horrific injuries, Mr Villagrana has a positive outlook.
"I have progressed a lot this week at the hospital and am very happy to be putting all my energy into the current rehabilitation process," he told AAP from his hospital bed.
The professional musician had been to Australia several times and performed in Melbourne with a jazz collective he helped form.
He was due to fly home to the US three days after the assault but instead faces a prolonged period in hospital.
Mr Villagrana doesn't remember much of the attack but managed to walk to a nearby pub afterwards and get help.
CCTV footage showed a shocking chain of events, including him being chased around a car park before being struck and falling to the ground where the assault continued.
After attending a concert with friends Mr Villagrana caught a tram, and while on board first came into contact with his alleged attacker, who got off at the same stop.
"He bothered me with questions and I avoided him and continued getting away. Unfortunately he did not let me get away."
Enea Myrteza, a 27-year-old homeless man, faced court on Friday charged with intentionally causing serious injury in circumstances of gross violence, intentionally causing serious injury to the musician and committing an indictable offence while on bail.
Myrteza did not apply for bail and will reappear in court on June 24 for a committal case conference.
"I believe I was targeted for no specific reason at all," Mr Villagrana said.
His father is making the trip from the US to support his son, and other people have banded together to help raise money for the musician's medical costs and rehabilitation.
There's a $10,000 goal and people can donate by visiting gofundme.com/us-muso-attacked-in-melbourne
Mr Villagrana is no stranger to Melbourne.
"For the full year of 2017 I made a living in Melbourne playing ukulele, singing songs on the streets and as a freelance trumpet musician," he said.
On the day of the attack, he had gone to Monash University to investigate enrolling in a music master's program.
He hopes to play again alongside his fellow Melbourne musicians.
