Hashirama was shown to be a very calm and collected person, as well as kind and caring, with a deep sense of loyalty, great charisma and negotiation skill. He saw the people of Konoha as a part of his own family, and his legacy took a firm root in the village. He was also shown to be a very wise and insightful man, as he passed on great teachings to Hiruzen. It was he who first believed that all Leaf ninja should show a true loyalty to each other, and that a Kage must be willing to put his life on the line for his village to set an example for all others. This belief of his is known as the Will of Fire.
Hashirama was the leader of the Senju clan, during the time that Konohagakure was found. He and his kinsmen went to the Uchiha clan (the only ones who could rival them in power), and asked for them to join hands and work together, thus creating Konohagakure. His opponent, Madara Uchiha, wasn’t thrilled with this idea, and warned his clan that the Senju would betray them, but the Uchihas shunned him, saying he was a trouble maker. He then left Konoha, and challenged Hashirama in a final battle, at the Valley of End. It was a hard and epic battle, but eventually Hashirama won and the safety of the village was restored once more.
Mokuton and Tailed Beast control.
He was most famous for his Wood Release jutsu, a kekkei genkai to mix earth and water-natured chakra to create this new element. By converting chakra into the source of life, he was able to create trees, causing them to grow to great sizes and manipulate them to diverse shapes and battle uses at will. It was said that this ability was used to create the very landscape and foundation that Konoha is built on. This ability was apparently unique for him, since none of his relatives were shown using the ability. Even Yamato, the only person to have proved compatible with Hashirama's genes, found his use of Wood Release to be much weaker in raw power. Yamato has also shown great skill in standard water and earth techniques, so it is presumed Hashirama could do water and earth techniques as well.
The ability Orochimaru most highly praised him for was his unique ability to control tailed beasts. Of all his considerable talents, it was this ability in particular that made Hashirama unparalleled in the shinobi world, so much so that he is regarded as one of the few people capable of completely controlling a tailed beast. At one time, he had many of the beasts in his possession. This ability was greatly amplified by his crystal necklace, which Yamato suggested was a requirement to control even Naruto's partial lapses into tailed forms.