There are several stories concerning the origin of the dish. In her book The Chinese Kitchen, Eileen Yin-Fei Lo states that the dish originates from a simple Hunan chicken dish, and that the reference to "Zongtang" in "Zuo Zongtang chicken" was not a reference to Zuo Zongtang's given name, but rather a reference to the homonym "zongtang", meaning "ancestral meeting hall" (Chinese: 宗堂; pinyin: zōngtáng).  Consistent with this interpretation, the dish name is sometimes (but considerably less commonly) found in Chinese as "Zuo ancestral hall chicken" (traditional Chinese: 左宗堂雞; simplified Chinese: 左宗堂鸡; pinyin: Zuǒ Zōngtáng jī).
According to the Taiwanese/Chinese word-of-mouth stories, the chicken was invented by General Zuo's wife, made for him after a victorious battle. He liked it so much that upon following victorious battles, he would have it made for all of his commanding officers as reward. It is however possible that this story was invented by the former family chef of the prominent Republican-era politician Tan Yankai, who simply put General Zuo's name on it to honor him, and to associate the dish with the famous man.
According to several sources, the recipe was invented by Taiwan-based, Hunan cuisine chef Peng Chang-kuei, who had been an apprentice of Cao Jingchen's, a famous early 20th century Chinese chef. Peng was the Nationalist government banquets' chef and fled with Chiang Kai-shek's forces to Taiwan during the Chinese civil war. There, he continued his career as official chef until 1973, when he moved to New York to open a restaurant. It is there that Peng started inventing new dishes and modifying traditional ones; one new dish, General Tso's chicken, was originally prepared without sugar, and subsequently altered to suit the tastes of "non-Hunanese people." The popularity of the dish has now led to it being "adopted" by local Hunanese chefs and food writers, perhaps as an acknowledgment of the dish's unique status, upon which the international reputation of Hunanese cuisine was largely based.   Ironically, when Peng opened a restaurant in Hunan in the 1990s introducing General Tso's chicken, the restaurant closed without success because the locals found the dish too sweet