Lionel Patea has been sentenced to life in prison for the murder of his former partner Tara Brown on the Gold Coast in September 2015.
Patea unexpectedly pleaded guilty in the Brisbane Supreme Court on the first day of his trial to killing Ms Brown.
The 25-year-old will have to spend at least 20 years behind bars before he is eligible for parole.
"You have to live every day of your life knowing that you deprived Ms Brown of her life and your daughter of her mother," Justice Debra Mullins said when handing down her sentence.
Ms Brown, 24, was bludgeoned to death with a metal fire hydrant cover after the former Bandidos bikie ran her car off a suburban Gold Coast street.
She had just dropped off their three-year-old daughter at day care when Patea chased down her hatchback with a 4WD.
Ms Brown had been hiding from him at a safe house and friends' homes since taking out a domestic violence order just days earlier.
Patea, handcuffed in the dock and dressed in a blue suit, sat emotionless as Ms Brown's mother Natalie Hinton earlier on Monday told the court of the "monster" who claimed her daughter's life.
"Tara was empathetic, warm and trusting," Ms Hinton said through heavy sobs.
Ms Hinton said Patea constantly sought validation from Ms Brown and used domestic violence tactics like gaslighting to destroy her self-confidence.
"The monster was now in control, she feared him," Ms Hinton said.
"He took full advantage of her vulnerability."
Ms Hinton said when she was told her daughter was in hospital, she knew in the pit of her stomach that Patea had found her and hurt her.
"I was oblivious to the extent of his sickening actions," she said.
"My whole world caved in around me as this misogynistic narcissist murdered my baby girl."
Witnesses to the incident saw the pair reaching speeds of more than 100km/h and Patea bashing on Ms Brown's driver's side window with both fists when she had to stop at red lights.
Patea ultimately rammed the back of her car, forcing her down an embankment and trapping her inside the overturned vehicle.
He used the metal slab weighing 7.8kg taken from the footpath to repeatedly bash her head, causing "non-survivable" brain injuries.
Nearby residents who heard the crash originally thought Patea was trying to free Ms Brown and helped him break a window to get to her.
It wasn't until they heard her crying out that they realised what he was doing and tried to stop him, but he fought them off.
A triple-zero call made by Ms Brown earlier captured the sounds of a dozen "thumping" sounds as well as her crying out "Lionel, stop, please help me".
Patea was also sentenced to the maximum five years' jail for breaching the domestic violence protection order against him. He will serve that concurrently with the murder sentence.
"It's difficult to perceive a more serious breach of the Domestic Violence Act," crown prosecutor Carl Heaton QC said.
National domestic violence helpline: 1800 737 732 or 1800RESPECT. In an emergency call triple-zero.
