Minato Namikaze (波風ミナト, Namikaze Minato) was the Fourth Hokage (四代目火影, Yondaime Hokage; Literally meaning "Fourth Fire Shadow") of Konohagakure. He was famous in life for his speed, leading to the moniker of Konoha's Yellow Flash (木ノ葉の黄色い閃光, Konoha no Kiiroi Senkō; English TV "Yellow Flash of the Leaf"). He died during the Nine-Tails' attack on Konoha, sacrificing his life to seal a part of the Nine-Tails into his newborn son, Naruto Uzumaki.
When Minato was in the Academy, his class-mate Kushina Uzumaki thought that he looked "unreliable" and even "girly". He dreamed of being acknowledged by the Konoha villagers by becoming the Hokage, which Kushina considered to be an impossible dream for someone like him.
Years later, however, when Kushina was kidnapped by Kumogakure ninja, Minato was the only one to pick up on the fact that she was leaving behind strands of her red hair to mark their path. After rescuing her, Minato explained that he had always admired her hair. No longer seeing him as "unreliable", she fell in love with him.
While physically resembling Naruto, Minato's personality is a strong contrast from Naruto's. Minato was collected and highly perceptive. During difficult events, he would remain composed, assessing the situation and devising appropriate plans of action.
Jiraiya said that Minato was a shrewd person, not one to do something without reason. Minato was also a very cautious individual as he set up at least two safe houses as well as scattered his Flying Thunder God Kunai over the outskirts of Konoha, presumably so he can intercept enemies that cross Konoha's borders. Ultimately enabling him to subdue the latter and remove his control over Kurama without causing more chaos in Konoha.
He also seemed well aware of the terror his reputation inspired in his foes. At the same time, he was considered a nice person and very respectful to others; he didn't like freely speaking about others' pasts, and would always talk to them with respect. He deeply cared for and loved his wife and child, becoming very nervous because of Kushina's pain during labour and even shedding tears of joy at his son's birth.
Minato also deeply cared for the village and all the shinobi, saying that they all are a big family. He also enjoyed reading, and took a special liking to reading Jiraiya's work in particular.
Minato was a fairly tall, fair-skinned man who on more than one occasion has been compared with Naruto in terms of physical appearance; both have bright, blue eyes and spiky, blond hair. Minato also had jaw-length bangs framing either side of his face. According to Jiraiya, Minato was considered to be very handsome.
According to Jiraiya, Minato was one of the most gifted shinobi who ever lived, even noting that there hasn't been another prodigious talent to reach his calibre. His abilities were so advanced that even the Fourth Raikage thought that no one would surpass him. Anko Mitarashi, in discussion with the Third Hokage about Orochimaru's immense strength and threat to the village, stated that she wished the Fourth had been alive to face him. Even, at a young age, he was able to rescue Kushina Uzumaki from three Kumogakure ninja alone, with little difficulty. During the Third Shinobi World War, flee-on-sight orders were given to enemy shinobi should they ever see him appear on the battlefield. In the anime, he alone defeated a thousand Iwa shinobi in one battle, later prompting Ōnoki to immediately consider accepting a peace treaty from Konohagakure. Minato was also capable of counteracting the Nine-Tails' attacks to the point that Tobi chose to stop Minato directly due to the short amount of time he could keep Kurama summoned. Even still, he quickly forced Tobi to retreat after unraveling his technique, making the man commend Minato's skills and worthiness of being Hokage.
During the Fourth Shinobi World War after being reincarnated he was able to give Obito Uchiha trouble despite being the Ten-Tails jinchūriki. He even managed to briefly overpower Obito while both himself and Naruto were in their Tailed Beast Mode and Sage Tailed Beast Mode respectively.