"She was overcome with remorse in interviews and suffers from profound grief and guilt for the circumstances of her granddaughter's death."
Smith avoided a term of life imprisonment and was instead jailed for 12 years, with a minimum non-parole period of six years.
But the Court of Appeal quashed that.
It said when it looked at the circumstances of Kalis' death, and her vulnerability, a life sentence was not manifestly unjust.
"We do not underestimate the significance of Kalis's vulnerability, and that Ms Smith deliberately set out to kill her granddaughter in a distressing manner. Ms Smith's offending involved a gross breach of trust," the judgment said.
"We believe, however, that Ms Smith's personal circumstances must be recognised with a compassionate response."
The Court of Appeal sentenced her to life imprisonment with a minimum non-parole period of 10 years - the least restrictive sentence it could impose.