The son of former New Jersey Gov. Jon Corzine killed himself in a Mexico City hotel this week.

Jeffrey Corzine, 31, was the youngest of Corzine’s three children with ex-wife and childhood sweetheart Joanne Corzine.

The exact cause of death was not released, but sources told The Post Jeffrey suffered from depression.

Steven Goldberg, a spokesman for the devastated Jon Corzine, confirmed in a statement: “The sad fact is that Jeffrey Corzine had been suffering from severe depression for several years and recently had been receiving treatment for what is a very painful and debilitating physical and mental ailment.”

“On Tuesday morning, he succumbed to his disease and made the tragic decision to take his own life.”

“Among many things, the Corzine family hopes Jeffrey will be remembered for his dedication to helping others overcome their struggles with depression and addiction, something to which he had been devoted for the past 10 years.”

The younger Corzine had a history of substance-abuse problems and had been in and out of rehab, sources said.

But he had been living in California and working as a drug counselor, and had appeared to have turned his life around.

Both of his parents had recently told friends that their son was clean.

“By all accounts, he was doing well,” a source said.

Jeffrey is survived by siblings Jennifer and Josh.

He had been living in a sunny, $2.8 million beachfront home in Malibu that his mom — who is remarried — helped him buy, records show.

Gov. Chris Christie and several others sent public condolences to the Corzines on Thursday.

“The Corzine family expresses its sincere appreciation for the kind thoughts and expressions of sympathy they have received from friends and many others,” Goldberg said of the outpouring.

“The family is planning a small, private memorial service, and they ask that people respect their privacy during this difficult time as they mourn the loss of Jeffrey.”

It is unclear when or why Corzine went to Mexico.

Jeffrey Corzine was a troubled teen, according to sources close to the family, and his father sent him to Pomfret, a boarding school in Connecticut, in hope of “giving him some direction.”

The two had a rocky relationship, a source said, but Jeffrey and his father bonded after the elder Corzine’s near-fatal 2007 car crash.

Jeffrey was a constant presence at his dad’s side during the pol’s 18-day stay at Cooper University Hospital in Camden.

“After that, Jeff seemed to straighten up a lot and the two of them grew much closer,” said one source.

Jeffrey was an avid poker player, and in 2012 he beat out former Yahoo president Sue Decker for the title in billionaire Warren Buffett’s annual high-stakes poker tournament.

He was also an artist and aspiring photographer, setting up the website jeffreycorzine.com several years ago.

On his Facebook page is a 2011 photo of him with President Obama.

The death of his youngest son is the latest in a series of challenges for the elder Corzine, who was ousted from Goldman Sachs in 1999 and is now being sued by regulators over the 2011 collapse of MF Global Holdings Ltd., the commodities broker he headed after leaving public office.

Additional reporting by Helen Kumari