Shortly before boarding his flight back to the US on Tuesday night, Schaefer apologised for his actions.
“I’m sorry. I’m always sorry. I’m always sorry,” Schaefer told AFP news agency.
“I was thrust into this situation, but I take full responsibility for everything I have done and I hope Sheila’s family finds peace.”
In 2015, an Indonesia court sentenced Schaefer to 18 years in jail and Mack to 10 years, for what the presiding judge called a “sadistic” killing.
Prosecutors had said that Mack – who was 18 at the time of the murder and pregnant – covered her mother’s mouth while Schaefer struck her in the head with a fruit bowl.
The body was stuffed inside a suitcase and left it in the boot of a taxi, prosecutors said. The driver later alerted police.
The couple was later discovered staying at another hotel in Bali.
Schaefer, then 21, said on trial that he had been defending himself after Wiese-Mack became angry after learning that her daughter was pregnant.
Mack was given a shorter sentence due to her lesser role and because she gave birth to a baby while on trial, the Bali court heard.
She too was released early and deported in 2021. She was arrested immediately upon arriving in the US and charged with conspiracy to kill a US national and obstruction of justice – and eventually sentenced to 26 years in jail.
Mack originally pleaded not guilty to the US charges on conspiring to kill a US national, but changed her plea after the prosecutors offered to ask for a shorter sentence.
Mack has given media interviews over the years from prison, where she recounted the incident and her troubled relationship with her mother.