After graduating, Takmine began practicing law in Honolulu. In 1983, he opened his own law office in Hilo, Hawaii as his father Yoshito Takamine resigned after 26 years in the Hawaii House of Representatives. The younger Takamine took his father's seat in 1984. Takamine maintains a house in Laupahoehoe but usually lives in Honolulu with his second wife who is a school official there. He has continued to practice labor law, focusing on workers' compensation cases. On behalf of the ILWU, whose ties to the Takamines go back decades, Takamine has pushed a lumber mill in Ookala, and a wood-burning power plant in Paauilo. Local residents are against both proposals. Takamine and his father played a key role in the controversial 1980s Kamehameha Schools (formerly Bishop Estate) decision to buy the Hamakua Sugar Company lands and then plant them in eucalyptus.