The man who dealt the punch that killed Brisbane teenager Cole Miller has been sentenced to seven years in jail for the "cowardly" attack.

New Zealand national Armstrong Renata fronted the Brisbane Supreme Court on Friday, having pleaded guilty to a count of unlawful striking causing death over the senseless January 2016 assault.

Cole Miller died after a one-punch attack in Brisbane's Fortitude Valley.

The 23-year-old was sentenced to seven years jail, with Justice Helen Bowskill describing the Fortitude Valley incident as "cowardly and violent".

She said his actions stole the life of a young man and "destroyed" those of his family and close friends.