Chai Shao was the son of Chai Shen, the Duke of Julu. He married Princess Pingyang, a daughter of Emperor Gaozu, the founder of the Tang dynasty, and distinguished himself as a general in the battles between the Tang Empire and Turkic invaders. On one occasion, when he was attacking the Tuyuhun forces which then threatened the frontier, his army was almost overwhelmed by a dense shower of arrows from the enemy's bows. However, Chai Shao sent forward some girls to play and dance to the Tartar guitar, which so fascinated the Tartar soldiers that they desisted from the fight to watch. Meanwhile, Chai Shao, by a rapid strategic movement, succeeded in surrounding them, and the whole force was cut to pieces. He aided Emperor Taizong in consolidating his control over the Tang Empire. In 628, he was appointed as the Governor of Huazhou in Shaanxi.