The oncoming car's passenger, Jonas Fischer received facial lacerations and abdominal bruising but was discharged from hospital the next day.
Tantrum received minor injuries as a result of the crash.
Ms Anderson had just completed two months of a 12-month stint at Hohepa, a school for the intellectually disabled, and had spent several months travelling around New Zealand. Mr Fischer was also a volunteer at Hohepa.
Represented by Scott Jefferson, Tantrum was sentenced to 12 months supervision and disqualified from driving for one year by Judge Tony Adeane.
Judge Adeane described the case as one of the most difficult due to the potential for a minor fault to lead to serious consequences, and put an imprisonment sentence to the side due to the circumstances.
"I accept that you are very deeply remorseful about what has happened," he said.
Judge Adeane said the deceased's family's response had been "remarkably gracious" and that they held no ill-will against Tantrum.
He said it was not appropriate to read out the family's statement.
The family had previously told Fairfax that in the spirit of the way Thea Anderson had lived her life they were not looking to blame anyone for the crash.
"We just feel a great sorrow for all the people involved and we have total forgiveness for anything that happened. Things are hard enough in this world, so we don't bear any ill-will," Ms Anderson's father, Thor, said last year.
Included in Tantrum's sentencing were conditions to undertake any directed counselling and psychiatric assessment; Judge Adeane telling Tantrum that while she may try to carry it on her own she would need to accept the support around her.
Tantrum is due to head to Palmerston North at the end of this week to begin tertiary studies at Massey University.