Toshiie Maeda was born in Araki, a village in Owari Province, home of the Oda clan. He was lower in the clan and ousted his brother from power to become the daimyo of the Maeda family of Owari Province. A vassal of the Oda clan, he served under the command of Nobunaga Oda. In 1560, he served in the Battle of Okehazama alongside his mentor Katsuie Shibata, where he was educated that strategy won battles, not numbers, as when he complained that the Oda had a handful of men to face an Imagawa horde, Katsuie told him, "would you rather die holed up in the castle?" Toshiie later fought at the Battle of Anegawa against the Asai and Asakura clans, but his nephew Keiji Maeda outdid him in battle, and Toshiie's feats in the battle were easily overshadowed. Toshiie fought in the Battle of Nagashino, the Battle of Tetorigawa, and the Second Battle of Kizugawa, gaining renown for saving his master from a horde of Uesugi in the second one.
Toshiie was forced to make a hard choice in 1583 after Nobunaga Oda died: he would have to side with either his role model Hideyoshi Hashiba, or his mentor Katsuie. Toshiie fought alongside Katsuie, but was convinced by Kiyomasa Kato to defect halfway through the Battle of Shizugatake. Toshiie fought against his old master in the second half of the engagement, but as the battle drew near its conclusion, he rushed to his master's side, hoping to rejoin him. However, his master set Shizugatake Castle on fire, and committed seppuku as it was razed to the ground. Toshiie remained with the Toyotomi, feeling grief about his betrayal of his master, but not necessarily regret. Toshiie lost his nephew after the battle, as Keiji wanted a life of his own and he left his uncle's protection, leaving him in a river. Toshiie only saw him one more time in 1590, at the Fall of Odawara, where the two did not say a word to one another, but fought side-by-side. Toshiie governed his clan's territory in Owari Province until he died of illness in 1598, the same year as Hideyoshi.