Ser Jared Frey is the fourth son of Walder Frey and the first from his second wife Cyrenna Swann. He is married to his cousin Alys Frey and has a son, Ser Tytos Frey, and a daughter, Kyra Frey, who is married to Ser Garse Goodbrook. Through them he has four grandchildren. Jared is tall, stooped and balding.

The Freys join Robb Stark early in the War of the Five Kings, after forcing him to agree to marry a daughter or granddaughter of Walder Frey. Jared is among the Freys captured at the Battle of the Green Fork and is ransomed. Later he is among the Frey force at Harrenhal with Roose Bolton. After Stannis Baratheon is defeated at the Blackwater by Tywin Lannister and Mace Tyrell, the Freys are worried that they will be unable to defeat the Lannister-Tyrell alliance, and one of Jared's half-brothers, Hosteen Frey, says Robb has lost the war and must make peace. Later news arrives at Harrenhal that Robb has broken the marriage pact, having taken Jeyne Westerling's virginity and married her to preserve her honour.

The Freys and Boltons secretly make an alliance with Tywin Lannister. They tell Robb they will join his cause again if his uncle Edmure Tully, Lord of Riverrun and Lord Paramount of the Trident, marries Roslin Frey, one of Jared's half-sisters. However the wedding is a trap. At the Red Wedding Robb Stark, his mother Catelyn, and most of his army are slaughtered. Jared's son Tytos Frey is killed by Sandor Clegane and his son-in-law Ser Garse Goodbrook also dies.

One of the victims of the Red Wedding is Ser Wendel Manderly, second son of Lord Wyman Manderly of White Harbor, the only city in the North. Meanwhile, Wyman's only surviving son Ser Wylis Manderly is still a captive of the Iron Throne at Harrenhal. Jared, one of his half-brothers Symond Frey, and a half-nephew Rhaegar Frey, bring Wendel's bones to White Harbor. They try to ensure the Manderlys swear fealty to the Iron Throne, offering the widowed Wyman Manderly a Frey bride, and the marriages of his granddaughters Wynafryd and Wylla Mandery to Rhaegar Frey and another of Walder Frey's grandsons Little Walder Frey.

When Davos Seaworth arrives in White Harbor to try and convince Lord Manderly to support Stannis, he finds the three Freys present. Jared claims during the Red Wedding Robb and the Northmen turned into wolves, Robb killing his half-nephew Aegon "Jinglebell" Frey and that Wendel was killed protecting Walder Frey. Jared also claims his son Tytos Frey and son-in-law Garse Goodbrook were slain by Robb Stark. Davos calls Jared a liar, at which Jared draws his sword and threatens to fight Davos, but Wyman forbids blood being shed in the Merman's court. Rhaegar claims that the war is over, Tommen Baratheon is the true King, and they must obey him, saying Robb Stark was a vile dog who died as he deserved, which Manderly agrees with. He then orders his cousin, Ser Marlon Manderly, to execute Davos.

However a common criminal he reassembles Davos is executed instead, and his head and hands, with the fingers shortened, are put on the gate. The head is dipped in tar and an onion stuffed into its mouth (supposedly a mockery of the onion on Davos' sigil) to distort the features further. For this supposed service to the Iron Throne, Wyman's heir is returned. At the feast to celebrate this Lord Manderly tells Davos privately that he is planning to restore the Starks, that Bran and Rickon Stark were not killed by Theon Greyjoy, and that he'll support Stannis if Davos recovers Rickon Stark from Skagos. Wyman says he will give the three Freys palfreys as guest gifts, which under the rules of guest right mean they will no longer be under his protection, implying Manderly will have them murdered.

Wyman Manderly and the three Freys apparently leave White Harbor for Barrowton, to attend the wedding of Roose' legitimized bastard Ramsay Bolton, and "Arya Stark" (really Jeyne Poole, who is being forced into the role), to legitimize Bolton rule of the North. However the Freys vanish on the way, Wyman claiming they rode on ahead due to the slowness of his train. Ramsay searches for the Freys but is unable to find them. Roose Bolton has come North with a Frey force and decides to hold the wedding at Winterfell to strengthen Ramsay's claim to Winterfell and force Stannis to battle, Stannis having taken Deepwood Motte and gathered some Northern support. At the wedding Wyman Manderly serves three large pies to the Freys and Boltons, which include Rhaegars' father Aenys Frey, eating some himself. Wyman asks for a song of the Rat Cook, who served to a King who had wronged him a pie containing his son. He was punished by being turned into a rat that could only eat its children for murdering a guest. These imply that the missing Freys were present at the wedding after all. Big Walder Frey thinks that Wyman had the Freys travelling with him murdered, and later Hosteen Frey accuses Wyman of their murders, which Wyman laughs at.