Time At Hogwarts

James was accepted into Hogwarts School of Witchcraft and Wizardry in 1971, where he was sorted into Gryffindor. It was here that he became friends with Sirius Black, Remus Lupin and Peter Pettigrew. James was an obnoxious child at Hogwarts, and liked to show off his talent as a Gryffindor Chaser. According to Lily Evans, James liked to ruffle his hair to make it look untidy, as though he had just gotten off a broomstick.

James liked to hex innocent students, especially Severus Snape from Slytherin house, purely because he could. The rivalry between James and Snape was a strong one, that, according to Remus Lupin and Sirius Black, was due to Snape being jealous of James’ Quidditch talent and popularity, especially with Lily Evans. Later, it was revealed that James and Sirius Black, who also had a strong dislike of Snape, insulted Snape as soon as they met on the Hogwarts Express. This in turn caused Snape to follow the Marauders around, trying to get them expelled.

James spent most of his academic career trying to attract the attention of a fellow Gryffindor, Lily Evans, whom he called by her surname. Lily, along with Snape, was one of the few who was unimpressed by James. Once, James hexed Snape and Lily ordered him to stop it. He said he would if Lily would go out with him. Once the hex had been lifted, Snape (regrettably) called Lily a Mudblood. It was this that caused more tension between Snape and James.

As second years, James, Sirius and Peter discovered Remus was a werewolf. James insisted that the monthly hazard of his transformation did not mean that Remus was abnormal. Sirius, Peter and James spent the next three years learning to become animagi to keep Remus company during his transformations. This is how James got his nickname, Prongs, as his animagus was a stag.

In their sixth year, after Sirius had told Snape about how to follow Remus under the Whomping Willow, James pulled Snape back just as Snape was near the Shrieking Shack. James had risked his life to save Snape, however Snape believed it was due to trying to save himself from expulsion, and hated being in James’ debt.

When James and Sirius were sixteen, the Potters allowed Sirius to move in, and he eventually became an unofficial member of the family. By seventh year, James had finally matured, and was appointed Head Boy, even though he had not been a prefect. He also managed to impress and start dating Lily Evans. He also stopped hexing innocent bystanders, though still occasionally hexed Snape.

First Wizarding War

After graduation, with Sirius as his best man, James married Lily Evans. They joined the Order of the Phoenix, along with Remus and Peter, in a fight against Lord Voldemort and his Death Eaters. In 1977, Sirius and James was caught in a motorbike chase with two Muggle Policemen. Although it started as fun, the pair were soon attacked by three wizards on broomsticks. Using their wands, James and Sirius raised the police car chasing them, and their pursuers crashed into it. James and Lily defied the Dark Lord three times in the next three years.

Due to his affluent parents, James inherited a large sum of money, and managed to support his family and, Remus, without a paying job.

On July 31, 1980, James became a father, to Harry James Potter. Shortly afterwards, Albus Dumbledore raised his concerns that they were in danger, as a prophecy had been made about someone fitting Harry's description who could defeat Lord Voldemort for good. Lord Voldemort was told this prophecy by Severus Snape. In October 1981, Dumbledore informed the Potters that a Fidelius Charm would be their best chance of protection. Dumbledore offered to be the Secret-Keeper, but James was adamant that it would be Sirius.

Some time after the decision was made, an anxious Sirius knew he was too obviously the choice, so he convinced James and Lily to use Peter as Secret-Keeper, keeping Sirius as a decoy. Unfortunately, the double bluff secret ended badly. Less than a week after the charm was cast, Peter betrayed Lily and James, and gave the information to Lord Voldemort. On October 31, 1981, the Dark Lord arrived at the Potters' house in Godric’s Hollow. James told Lily to take Harry and run whilst he battled with Lord Voldemort, giving them enough time to escape. Lord Voldemort killed him with the Killing Curse.

After Death

After James and Lily’s brutal murder, their son Harry was raised by Lily’s Muggle sister, Petunia Dursley, her husband Vernon, and their son Dudley. At age 11, Harry attended Hogwarts, where Snape had become Potions professor. Snape treated Harry with disdain, stating Harry was  "arrogant as his father, a determined rule-breaker...attention-seeking and impertinent." The only thing that kept Harry safe from Snape was being Lily's son, as his eyes always reminded Snape.

Harry saw visions and spectral forms of his parents throughout his time at Hogwarts. In 1991, he saw them in the Mirror of Erised. In 1995, he saw them during his duel with Voldemort thanks to Priori Incantatem. Priori Incantatem is the "reverse spell" that reveals the last spell cast by a wand; it also occurs when two wands with the same core are forced to duel. In this case, Harry's wand forced Voldemort's wand to spit out the "ghosts" of its previous spells. In 1998, during the second Wizarding War, Harry saw them through the Resurrection Stone, one of the three Deathly Hallows. Here, Harry was told his parents were extremely proud of him, and that they would stay with him until the very end.

James’ daughter in law was Ginny Weasley, who gave him three grandchildren. Harry’s eldest was called James Sirius, next was Albus Severus, and finally Lily Luna.