He was a capable supporting chancellor to Song Jing, and he was also immensely gifted literarily, ranking with Zhang Yue as the two great literary figures of their time.
At that time, his father Su Gui was serving on the staff of Emperor Gaozong's son Li Dan, the Prince of Yu.
During the reign of Emperor Gaozong's wife Wu Zetian, Su Ting passed the imperial examinations (before he was 19) and was made the magistrate of Wucheng County (烏程, in modern Huzhou, Jiangsu).
In 710, Emperor Zhongzong died suddenly—a death that traditional historians believed to be a poisoning carried out by his powerful wife Empress Wei and her daughter Li Guo'er the Princess Anle, so that Empress Wei could become "emperor" like Wu Zetian and Li Guo'er could be crown princess.
The chancellor Li Jiao, who was Su Ting's superior and who was himself known for great literary talent, commented, "The Sheren thinks as fast as a gushing spring.
Su Ting inherited the title of Duke of Xu and left government service to observe a mourning period for his father.
Soon thereafter, Emperor Ruizong tried to recall him to government service as the deputy minister of public works (工部侍郎, Gongbu Shilang), which he declined—and when Emperor Ruizong sent the official Li Rizhi to visit Su Ting to urge him to return to government service, Li Rizhi saw that Su Ting's mourning was deep and genuine.
Emperor Xuanzong thus made Su Zhongshu Shilang—and gave him the unprecedented honor of sharing the food normally served only to chancellors.
However, as far as making important decisions and being knowledgeable about governance, as well as being fair and impartial, Su Ting greatly exceeds his father.Later in 717, there was a controversy over whether Emperors Zhongzong and Ruizong, as brothers, could both be worshipped at the ancestral temple.
One day, while Emperor Xuanzong was watching a play, an actor dressed as the Hanba, and stated: There are over 300 people saddled with unfair judgments.
Song sent the imperial censor Xiao Yinzhi (蕭隱之) to the region to be in charge of collecting the damaged coins and taking them out of circulation.
Also in 725, when Emperor Xuanzong offered sacrifices to heaven and earthat Mount Tai, he had Su draft the text of the monument there.
It was said that Su was frugal and did not care about money—and that he shared his salaries with his younger brothers and family members, with no savings left.