Matthew Fuller, 25, was electrocuted on October 14, 2009 while installing foil insulation in the ceiling of a home in Meadowbrook, south of Brisbane.
His girlfriend and co-worker Monique Pridmore, 18, sustained severe electrical burns to her leg.
Their employer, QHI Installations Pty Ltd, was charged with failing to conduct its business in a way that was electrically safe.
Director Christopher William McKay and his father, company manager Christopher John McKay, were also charged with failing to ensure the company complied with its obligations.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
On Friday, in the Beenleigh Magistrates Court, Christopher John McKay pleaded guilty to a charge of failing to ensure the company complied with its obligations.
A guilty plea was also entered on behalf of the company.
But the charge against Christopher William McKay was dropped.
A sentencing hearing is under way.
The government axed its $2.45 billion insulation scheme in April 2010 after the death of four installers, 100 house fires and accusations of fraud and unsafe work conditions.
