As a child, Jiraiya and his former teammates, Orochimaru and Tsunade, were students of the Third Hokage. After leaving the Third's tutelage, he discovered the residence of the toads, who trained him to call upon them in battle. During this time a prophecy concerning Jiraiya was told, dictating that he would travel the world while writing a book and meet a child who might bring either great peace or great chaos to the world. During his travels, Jiraiya and his former teammates fought with Hanzo, who rewarded their ability to survive his attacks through the title of "Legendary Three Ninja" (Densetsu no Sannin). Soon after this Jiraiya met Nagato, a boy he believed to be the child from the prophecy. Jiraiya trained Nagato and his friends, hoping to steer the boy down the path of good before returning to Konoha.
Upon his return, Jiraiya became the sensei of Minato Namikaze and two other unknown Genin. Years later, when Orochimaru betrayed Konoha and fled the village, Jiraiya pursued him, trying to convince his friend to come back. He failed in his attempt and resumed his travels of the world, wanting to follow Orochimaru's movements as well as the organization Orochimaru eventually joined, Akatsuki. Sometime around this time, Jiraiya was made the godfather of Naruto Uzumaki by Minato and Kushina Uzumaki because they decided to name him after the lead character in Jiraiya's first book.
Despite the fact that he periodically leaves Konoha, Jiraiya has maintained a strong allegiance with his hometown. He will also often come back to Konoha, even if it was to just spy on women in the bathing house. During Orochimaru's invasion of Konoha, he helps fend off the invading forces in order to protect the village. When Konoha finds itself in need of a new Hokage after the Third Hokage's death, Jiraiya volunteers to look for Tsunade so that she can become the Third's successor. He turns down the position himself, believing he isn't qualified for the title due to his inability to have saved the Third or Fourth from death. After he finds Tsunade and begins to suspect that she may be assisting Orochimaru, he makes it clear that he will kill her if she betrays the village. Tsunade ultimately turns out to be loyal to Konoha, and Jiraiya joins her in attempting to defeat Orochimaru.
Jiraiya is a self-proclaimed super-pervert with no equal and a frequent voyeur, going so far as to create the Transparent Escape Technique (Tōton Jutsu, English TV "Transparency Jutsu") to allow him to spy on naked women without being caught (doing "research" as he calls it). He never actually hides his perversion and even seems proud of it, as seen when he told the Third Hokage about it when he was still a child. Despite this, Jiraiya doesn't like being called Ero-sennin (literally "Perverted hermit", English TV "Pervy Sage") by Naruto in front of others. His perversion has been used against him on occasion, as seen when two Akatsuki members use a hypnotized woman to draw him away from Naruto. While their effort initially succeeds, Jiraiya eventually sees through their plot due solely to the fact that women do not typically express interest in him. His peeping habits have also caused him great injury on one occasion; when caught spying on Tsunade in his younger years, she proceeded to break both of his arms, six of his ribs, and ruptured a number of organs in fury.
During his travels, Jiraiya began to write a number of books. His first book, a sort of autobiography about a character named "Naruto," found little success. To improve the sales, he wrote a book based on his experiences in love, which came to be known as "Come Come Paradise" (Icha Icha Paradaisu, English "Make-Out Paradise"). The book proved an instant success and has since spawned a number of sequels. The popularity of the Icha Icha series seems to have paid off well, as Jiraiya's checkbook reveals that he is fairly wealthy (Naruto exclaims that there are quite a few zeros at the end). Despite his wealth, Jiraiya is not above taking Naruto's money and spending it on sake and women.
Jiraiya in "Sage Mode"
Jiraiya is known as the "Toad Sage" (Gama Sennin?, English TV: "Toad Mountain Sage") due to his utilization of a number of toad-related jutsu. Many typically deal with summoning toads, and he has risen to a level of ability that allows him to summon Gamabunta. He can even summon the nearly indestructible esophagus of a great, fire-breathing toad with Summoning: Toad Mouth Bind (Kuchiyose: Gamaguchi Shibari, English TV "Toad Mouth Trap"). Once the jutsu has been used to cover the area, Jiraiya can control it as he pleases and uses it to trap most ninja. In desperate situations, Jiraiya is able to switch into a "Sage Mode".
Because he has not yet learned how to utilize the mode by himself, he must summon two elder toads to assist him, who further aid him by contributing their own techniques to a battle. Despite the advantages the form allows him, it gives him webbed-hands, a large nose, and a number of warts, and thus he dislikes using the form since his new look scares away girls.
In addition to calling upon toads for aid in battle, Jiraiya has a number of jutsu he can use independently. He uses Earth Release: Swamp of the Underworld (Doton: Yomi Numa, English TV "Earth Style: Dark Swamp") to create a large swampland under a target that is capable of completely engulfing them. He can spit either fire or oil from his mouth, allowing him to burn or drench opponents as he pleases. Jiraiya has also been shown to use his hair for jutsu, and can grow and sharpen it to surround him as a shield, protecting him from harm and injuring attackers, or use it to bind and impale opponents. His Toad-Silhouette Control Technique (Gama Daira Kage Ayatsuri no Jutsu) allows him to merge with the shadows of others, and through this he is able to take complete control of their body. Jiraiya was taught how to use the Rasengan by Minato, and has since developed a variant called Super Great Ball Rasengan (Chō Ōdama Rasengan), though its capabilities are currently unknown. He is, however, not well suited for genjutsu, and thus cannot effectively utilize it in battle.
Jiraiya has been shown to be very knowledgeable with sealing jutsu, and has used a number of them throughout the series. When first meeting Naruto, he quickly deduces that the seal on Naruto's stomach keeps the Nine-Tailed Demon Fox sealed within him though also allows its chakra to mix with his own. He later creates a method of suppressing the demon fox's influence over Naruto through the Subdue Seal (Ō Fūin), which activates by simply coming into contact with Naruto's body. In addition, he can utilize the Fire Sealing Method (Fūka Hōin, English TV "Fire Seal") to contain a fire within a scroll for future study.