Eighteen-year-old Matthew Bent was sentenced Thursday for an aggravated battery conviction.
Two other teenagers are already serving prison time for their roles in the attack on Michael Brewer, who was then 15.
Brewer survived by leaping into an apartment complex swimming pool but suffered severe burns.
Trial testimony showed the attack stemmed from a dispute between Bent and Brewer over a marijuana pipe.
Witnesses said the boys with Bent found a jug of rubbing alcohol and decided to pour it on Brewer.
Bent was acquitted in June of the more serious charge of attempted murder.