His case claiming wrongful dismissal was expected to be heard next week.
A spokesperson for Humphrey told the Herald he had now resigned to engage with other professional opportunities.
"He wishes his former colleagues in Community and Public Health all the best for the future."
At the hearing in April, Humphrey's lawyer Carolyn Heaton argued the longer he was away from his position and no longer practising, the more difficult it would be for him to get back into the industry.
She also argued it was likely to permanently damage his career.
"This has been an incredibly bruising experience for the plaintiff [Humphrey], who has been criticised for speaking out."
CDHB lawyer Andrew Shaw said the breakdown in Humphrey's relationship with the health board started because he was unwilling to accept he was "directly responsible" to his line manager, and his interpersonal relationships with his coworkers.
Despite the medical officer of health role being a statutory appointment by the Ministry of Health, it is still considered to be under the employ of the CHDB, which Shaw said was never accepted by Humphrey.
"This has been snowballing over 10 or 15 years and people came out and started saying enough is enough."
Humphrey had been employed by the CDHB since 2000 and was a Medical Officer of Health (MOH) for most of that time.
He has been the public face of many Canterbury health issues since he took up the position.
