Walter Palin was a loan shark and was a member of the mob (the Atkinson, Basco, and Veneziano crime families).
Walter first appeared in the company of David Chow as an unknown man, for whom David seemed to have been doing favors. It was revealed that Walter was blackmailing David because he had owed him (and his bosses) money. Nobody was quite sure if David really loved Nikki Newman, or if he was using her to get to her money. Though he had professed time and time again that he loved Nikki (both to his loan shark and to Nikki herself), he had also told Walter he was planning a hit and attempted to poison Nikki with a glass of sparkling cider. At this time, a mysterious man, Walter, began appearing in Genoa City. He tracked down David but called him "Clark", wanting the money David owed him, and asking him why he changed his name.
David's wife Nikki wasn't suspicious of Walter since David introduced him as a longtime friend. David wanted to prevent Nikki from finding out about Walter. Walter seemed to be the only one that knew about David’s "Clark" identity. Walter kept pressing David, threatening to tell Nikki about "Clark". After getting into a fist-fight with Walter at a restaurant, David had to finally confess to a shocked Nikki that he had a gambling problem, and that Walter was a loan shark from whom David had borrowed money. This brought their relationship to the breaking point. Nikki eventually decided to forgive him. Despite David's protests, Nikki paid off the $250,000 David owed Walter.
Once David paid off his debt with Nikki's money, Walter left, saying that he would eventually return. David tried to stay away from his past but couldn't. David wanted to win back Nikki's trust and gain notoriety as an upstanding executive at Jabot Cosmetics. Nikki told David to get therapy for his gambling addiction, and he said he would. However, after Nikki left, David tossed aside the list of self help groups and addiction therapists she had given him, determined to stop gambling "on his own." This left him prey for the new Chief Operations Officer of Jabot, Brad Carlton. Brad felt David was ill suited for the co-CEO position at Jabot, and began to hatch a plan to get David to gamble once again.
Brad set David up with his bookie to lose bets, holding impromptu poker nights at his place and lending David money to cover his losses. As of June 2008, David's debts were starting to build up once more, forcing him to seek a loan from Walter after losing $40,000 in a horse race. His gambling habits continued to escalate until finally he demanded a divorce from Nikki because he feared that he would gamble away her money just as he had with his ex-wives. Soon thereafter, while on a business trip, he met with Walter in Las Vegas at a casino. While there it was revealed that David, acting on Walter's behalf, played a part in the death of Ji Min Kim. It was also revealed a few weeks later that Mina King died under suspicious circumstances.
In mid-July 2008 detective Paul Williams discovered that David's real name was Angelo Sarafini, and that he was a hit man for the mob. Investigation in David's past led by Paul, revealed Walter's real name, Tony Amato. He and David had known each other for years. Walter was worried that he might be compromised and ordered David to kill Skye Lockhart by his orders, but their business didn't end there. Nikki, after having learned about another lie of David's, told him it was over, but they both agreed to announce their separation after the charity ball gala that was being held in Genoa City. David ordered a vial of liquid morphine and poured it in Nikki's drink, intending to kill her, but he never saw his plan develop because she was rescued by Paul and JT Hellstrom.
Walter continued blackmailing David, who finally decided to cut all links to Walter. Walter didn't take the news well, and he ordered David's wife killed. Later that night, David was killed in a car accident orchestrated by Walter. Walter didn't know that in the car, where Nikki was supposed to be, David took Sabrina Costelana Newman and the two of them ended up in an accident, and eventually died. Walter ran away to a secure location in Mexico, but was followed by Victor Newman, who was seeking revenge for the death of Sabrina. Sabrina's death had led to a downward spiral for Victor who was out for revenge against Walter, the man responsible for Sabrina's death.
Victor went to Mexico planning to kill Walter. He went along on a boat ride with Walter where Victor confronted him for what he had done. Walter's body was found the following morning, but his death was never resolved by the police. Heather Stevens called the Mexican authorities and asked about Walter’s body washing ashore. An international warrant for murder is issued in the Walter Palin case. When Heather got out of bed, she asked to borrow Adam Newman's computer and was surprised at a photo he had on his screen. She told him it was Tony Amato/Walter Palin and she asked what he knew about the guy.
He tells her that he was on a boat that went down in a storm and he didn’t survive but the other man on the boat did. She asked who the other man was and he told her it was Victor. Heather wasn’t sure if there was even a crime committed, even if Victor did confront Walter. Brad defended himself to Sharon Newman saying David had this sickness a long time before David met Brad. She asks Brad how he could put himself into this position saying he could go to jail over all this. She said hopefully once they found Walter, Brad would be able to tell the cops that he didn’t have any connection in this case and it would clear him of any charges. Heather talked to Brad at the Genoa City Athletic Club but Brad didn't seem to want to talk very much.
He told her that he couldn't talk about someone he never met when she asked about Walter. He said David must have put his money in Walter’s account but once they found Walter, Walter could verify that they never met. Heather handed Brad an autopsy photo saying Walter was dead, and, since David was dead, too, the one left holding the bag was Brad. Heather got back to her suite and was surprised to find Adam there. She said that the district attorney was excited that they were making headway on the Walter Palin case. Adam and Jack Abbott conspired to frame Victor for Walter's death. While Victor was gone, Jack and Adam created and published a fake diary of Victor's, forging his confession to the murder.
Ashley Abbott and Victor returned to Genoa City and Victor was arrested for the murder of Walter. Nikki's eyes grew large as Victor said to her, "I got a tip that they're investigating me - did you tell the authorities that I killed Walter Palin?" Victor was cleared of the crime and only Adam was arrested for his part in it as Jack profoundly covered his tracks so as to not be deemed responsible whatsoever. Heather informed both Jill Abbott and Brad that the FBI and SEC were dropping all charges against them since both David and Walter were dead.