The 27-year-old man was working as a multi-drop delivery driver for pallet distribution firm H&M Distribution when the accident happened on 18 May 2017.
The company pleaded guilty to breaching s 3(1) of the Health and Safety at Work Act and has been fined £60,000.
Cheltenham Magistrates' Court was told that the worker was given a "brief" induction at the company's Gloucester depot before starting work the same day.
However, an address on his route was incorrect and the order of 12 beer was kegs was undeliverable. The worker was moving the kegs with a pallet truck to access the next load when he fell from the raised tail lift on to the road.
Several kegs of beer fell and struck him, resulting in a traumatic brain injury and facial fractures that required metal plates to be inserted into his skull.
Investigating, the Health and Safety Executive (HSE) found the worker had no previous experience with the type of pallet truck or tail lift involved in the accident. He had not been trained to use the machinery safely, nor was he made aware of safe working practices for operating a pallet truck on a tail lift.
It said H&M Distribution failed in its duty to carry out checks on the injured person's competence and previous experience and, as a result, did not provide adequate training.
The company was ordered to pay prosecution costs of £7,203 also.
After the hearing HSE inspector Berenice Ray said: "Employers who use agency workers or contractors have a responsibility to firstly establish the workers' competence, [considering] their level of experience and familiarity with the work and work equipment, and then provide the appropriate level of training to ensure the work is done safely.
"If appropriate training had been provided, the life-changing injuries sustained by the agency worker could have been prevented."
In August 2014 a H&M Distribution delivery driver was paralysed from the chest down when he was crushed between two vehicles at a yard in Sandy, Bedfordshire, resulting in a £150,000 fine.
