Police say it started with a crash on the Bruce Highway at Palmview, on the Sunshine Coast, just after midday on Monday.
They believe a red Porsche Macan crashed and caused a collision, which involved multiple vehicles.
A man armed with a gun got out of the Porsche, approached a white SsangYong Rexton and shot the male driver in the arm, police said.
Investigators do not believe the two men knew each other.
The man with the firearm then allegedly stole the Rexton, fled the crash site and later hijacked another car before being arrested.
Two people caught up in the collision who were in a different car were badly injured, with a woman dying and a man taken to hospital.
The first stolen car was found crashed in Landsborough and police allege the man then stole a grey Mazda 3.
Queensland Police Chief Inspector Jason Overland said a young male doing driver training with his mum and dad were inside that car when it was "hijacked".
"I've given up trying to work out why," Mr Overland told reporters at Caloundra on Monday afternoon.
"It's just a tragedy and we're doing all we can to address what's left."
He asked drivers to be patients as police were processing three separate crime scenes.
Anyone with information about what happened has been urged to contact investigators.
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