Toshimasa was the second son of Maeda Toshiie and was given a 215,000 koku fief in Noto province after his father's death (1599). He supported Ishida Mitsunari during the Sekigahara Campaign and had evidently plotted to assassinate Tokugawa Ieyasu beforehand. After Mitsunari's defeat, Toshimasa was forced to retire and hand his lands over to his elder brother Toshinaga. He afterwards went to Kyoto and took the tonsure.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005