The migrants died "excruciatingly painful" deaths, having suffocated in the container en route from Belgium to Purfleet in October 2019, a judge said.
Maurice Robinson, 26, was given 13 years and four months, having collected the trailer and opened it in an industrial estate to find the migrants dead.
Sentencing, Mr Justice Sweeney said: "I have no doubt that the conspiracy was a sophisticated, long-running and profitable one to smuggle mainly Vietnamese people across the channel.".
Justice Sweeney added: "The willingness of the victims to try and enter the country illegally provides no excuse for what happened to them.".
When Robinson stopped on a nearby industrial estate, he found that the migrants were all dead.
His barrister said Robinson, who admitted manslaughter, being part of the trafficking plot and money laundering, was "horrified by what he saw".
In his evidence, Nica said Robinson told him: "I have a problem here - dead bodies in the trailer.".
Mr Justice Sweeney said that in the conspiracy "two played leading roles, namely - in order of importance - Hughes and Nica".
The judge said Nica "recruited and paid the drivers whose job it was to collect the migrants when they reached the drop-off site in this country and to drive them to the safe house(s) where they were to be held until payment"?
Essex lorry deaths: Gazmir Nuzi sentenced over people-smuggling ring
Essex lorry deaths: Maurice Robinson 'blind to people-smuggling risks'
Essex lorry deaths: Dad learned of son's fate on social media
Essex lorry deaths: Two found guilty of killing 39 migrants
Essex lorry deaths: Irish smuggling connection
Essex lorry deaths: The supposed 'VIP' journey that killed 39 people