Justice Michael Croucher handed down the sentence in the Victorian Supreme Court on Friday as Mrs Clay's family and friends watched on.
Lynn, 58, blinked and stared straight ahead as he learnt of his 32-year jail term. He will be eligible for parole after 24 years.
Greg Lynn was convicted of murdering Carol Clay but acquitted over her lover Russell Hill's death. (HANDOUT/VICTORIA POLICE, 9NEWS)
A jury in June found Lynn guilty of shooting Mrs Clay in the head at a Victorian high country campsite in March 2020.
He then placed her body - and the body of her lover Russell Hill - into a trailer and then drove them to a remote bush track.
Lynn returned seven months later after the COVID-19 lockdown lifted to burn their remains into more than 2000 bone fragments.
The former Jetstar pilot maintained his innocence, claiming the deaths of both Mrs Clay and Mr Hill were accidental.
After a month-long trial, the jury found him guilty of murdering Mrs Clay but acquitted him over Mr Hill's death.
Lynn continues to deny the murder but conceded he destroyed the couple's remains and much of the campsite's evidence.
Justice Croucher described the killing as "violent, brutal and horrific" when he handed down the sentence on Friday.
Greg Lynn blinked and stared straight ahead as he learnt of his 32-year jail term. (Paul Tyquin/AAP PHOTOS)
Burning the remains was an aggravating feature and showed Lynn's moral culpability was high, Justice Croucher said.
"This was just a terrible thing to do, hence my conclusion this is a very grave murder," he said.
Justice Croucher noted the "profoundly moving" statements from Mrs Clay's loved ones, who remembered her as a loving grandmother.
The judge also broke down in tears as he acknowledged Mr Hill's family, including his wife Robyn.
While they were not considered victims in the eyes of the law due to acquittal, Justice Croucher said it was clear they were also in pain.
"As one person to another, as a matter of common human decency, I should acknowledge their plight, their agony, their suffering - and I do," the judge said.
He also took into account that Lynn led police to the remains and apologised for his "despicable" actions after the murder.
The judge said that "tempered" the aggravating post-offence conduct, although only modestly.
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