In his closing statements to the court Barry Roux said that just as a woman might kill an abusive husband after many years, so the Paralympian has built up an exaggerated response to danger.
Oscar Pistorius arrives at court for closing arguments
He pleaded with Judge Thokozile Matilda Masipa to consider his actions in the context of his lifelong disability. "Don't look at (that night) in isolation," he said.
This is his last chance to convince the judge of his client's innocence. The athlete has claimed that he shot his girlfriend Reeva Steenkamp after mistaking her for an intruder.
On Thursday for the first time both Reeva's father and Oscar's were in court for proceedings. For the last few years the champion sprinter has been estranged from his father Henke, but on Friday they embraced before sitting down.
Barry Steenkamp has been absent for most of the trial after suffering a stroke in February, which his family blamed on the stress of the situation.
Oscar's father Henke Pistorius is in court for the first time
On Friday, Mr Roux conceded that his client was "guilty of negligence" on the charge related to an incident in a restaurant separate from Reeva's shooting. On that occasion Oscar's gun went off as he showed it to a friend.
"He's guilty, m'lady, guilty on the first alternative, he negligently used that firearm," his lawyer said. However, he still insists it is not clear if the gun was working properly and that the athlete had never avoided blame.