Adrian Bayley, 41, previously admitted raping and murdering the County Louth woman in Melbourne last September.
The 29-year-old was attacked as she walked home from a nearby bar.
The court heard that Bayley had a "degree of sexual depravity rarely seen" in the Australian system. He will be sentenced next week.
Evidence was also given that Bayley was on bail for an assault conviction and on parole for previous rape convictions at the time he attacked Ms Meagher.
The court was told that Bayley had a history of violent sex attacks and had previously raped 21 times, the first time when he was 18 years old.
Mrs Meagher's husband, family and friends described to the court the devastating impact her murder and rape have had on them.
Her father George McKeown spoke of how her killing had destroyed their family and stolen her future.
The court heard how her husband Tom is haunted by what happened, wishing he could have told her he loved her in her final moments.
He said he suffers anxiety and panic attacks now, and is "only half a person" without his wife who he described as having "a beautiful mind and a brilliant soul".
Bayley's barrister told the court that the killer was sorry for what he had done and was seeking a life sentence, but without a mandatory minimum duration.
Ms Meagher, who was originally from Drogheda, moved to Australia from Ireland in 2009 with her husband.
She worked for ABC radio but went missing during a night out with colleagues.
Her body was discovered six days later buried on the outskirts of the city.
The man who raped and murdered Irish woman Jill Meagher has been described as a "violent sexual offender".