Swiftstar is a dark gray-black tom with a long tail.
Swiftstar was an ancient WindClanleader in the forest territories, and his deputy and medicine cat were Milkfur and Larkwing, respectively. At the time when SkyClan was exiled from the forest, Swiftstar was the first to refuse Cloudstar's request to give up territory for SkyClan. He coldly stated that SkyClan couldn't go around begging for territory. Later in StarClan, Swiftstar gave Leafdapple a life for selflessness to use well in the service of her Clan. At her ceremony, he and the other leaders confessed their wrongdoing.
Swiftstar, an ancient WindClan leader, is complaining about wasting time, saying that the Gathering should start. He snorts that WindClan has better things to do than sit around waiting for cats who can't be bothered to come at the proper time. When he asks Cloudstar why SkyClan is late, Cloudstar doesn't reply. Swiftstar then remarks that it looks like Cloudstar brought his whole Clan, and is puzzled why. Cloudstar replies saying that it is true, and reveals that Twolegs have destroyed SkyClan's territory. When Cloudstar asks for more territory, Swiftstar coldly tells him that he can't just walk in and ask for territory, since they can barely feed their own Clans as it is.
After the other leaders make remarks of their own, Swiftstar adds that only WindClan knows how to catch rabbits, and that there is nowhere on WindClan territory where SkyClan could make a camp. Swiftstar supports Redstar's suggestion that SkyClan should leave and, with a hint of a snarl in his voice, tells them to go somewhere far away so SkyClan can't steal another Clan's prey. Swiftstar argues with Larkwing, his medicine cat, about whether or not SkyClan's leaving is the will of StarClan.
Much later, Swiftstar appears with the other leaders: Redstar, Birchstar, and Dawnstar, the Clan leaders at the time of SkyClan's departure, during Leafstar's leadership ceremony. He tells Cloudstar that when he walked the forest he never told any cat he was sorry, but he says it now; what the leaders did was wrong. Swiftstar hardly gives Leafdapple time to receive Birchstar's life before he gives Leafdapple a life for selflessness, to use well in the service of her Clan. Swiftstar tells Firestar that the leaders had paid for their wrongdoing. None of the leaders could rest easily after SkyClan was gone, and guilt clawed at them for the rest of their lives.
Although unnamed, Swiftstar is mentioned by Firestar, when the old ThunderClan leader is talking to Bramblestar about SkyClan. He says that the leaders of ThunderClan, WindClan, ShadowClan, and RiverClan had to deal with the consequences of their actions after being responsible for driving out SkyClan. Firestar goes on to tell Bramblestar that each of these leaders had come to visit Leafstar during her leadership ceremony, and in turn, gave her a life. Firestar says that this served as not only an apology, but a reminder that one Clan is not able to survive alone.
At a Gathering, Swiftstar and his Clan attend, just like normal, and when every leader is finished sharing their news he invites them to go join the mingling cats below, and comments on how he is getting old to be sitting on the Great Rock for extended amounts of time.
At the next Gathering, the Gathering where SkyClan takes its leave, Swiftstar demands what kept SkyClan. He exclaims that Cloudstar must have brought his whole Clan, and Cloudstar confirms it. When SkyClan's leader asks for territory since SkyClan's home has been destroyed by Twolegs, Swiftstar is the first to respond. He refuses, coldly saying that Cloudstar can't just walk in begging for territory while the other Clans are barely salvaging as is. After Birchstar tells Cloudstar that SkyClan cats cannot fish, Swiftstar agrees that only WindClan can easily get rabbits and birds that are on the moors. After Cloudstar hopelessly asks what to do and Redstar tells them to leave, Swiftstar agrees with Redstar that they should leave and find a faraway place where they cannot steal prey. Swiftstar's medicine cat, Larkwing, disagrees, but he tells her the moon is still shining, and if SkyClan was not meant to leave, clouds would obscure the moon and the sky.
Although not mentioned by name, it is mentioned on Cloudstar's and Skywatcher's page that when Twoleg dens started to destroy SkyClan territory, Cloudstar looked to his rival Clans to help him and his Clan survive. Instead, Swiftstar and the other leaders protested that sharing territory would be impossible, that SkyClan could not catch different prey, that if there were only four Great Oaks in the hollow, perhaps there were only meant to be four Clans.