Li Yong, named Jianhou, was from Jiangxia. The grandnephew of Li Yong, the governor of Beihai. When his father was in love, he left his family behind when he was an official. During the Dali period, Li Yong was elected as a Jinshi, and his calligraphy was awarded a high level, and he was awarded the secretary's official calligraphy. Recruited by Li Huaiguang, he was repeatedly promoted to the position of Supervisory Censor. When Li Huaiguang rebelled against Pujin, Li Yong, his mother and wife were trapped by thieves. He was worried about harming his relatives, so he falsely told Li Huaiguang: "Because my brother is ill in Luoyang, please let my mother go to visit him." Li Huaiguang agreed and warned him. His wife and children were not allowed to follow him, but Li Yong sent them all away. Later, Li Huaiguang learned about it and questioned him. He replied: "I have military status and cannot accompany my mother. Why don't I let my daughter-in-law go with her mother-in-law?" Li Huaiguang could not convict him. At that time, Li Yong and former prime minister Gao Ying were in the rebel court, so they secretly reported to the emperor the actual strength of the rebel army and the situation of their attack. Dezong personally gave them an imperial edict to comfort them. Later, when the matter was revealed, Li Huaiguang ordered the three armies to form a majestic formation and summoned Gao Ying and Li Yong for questioning. Li Yong's words were fierce and generous, and the three armies praised his loyalty. Li Huaiguang did not dare to kill him and imprisoned him. When Li Huaiguang died, Ma Sui personally went to the prison to pay tribute and said that Li Yong was working for Hedong. Soon after, because his opinions were not accepted, he resigned and returned to Luozhong to recuperate. Xiangzhou Jiedu envoy Li Gao, the successor of King Cao, sent a gift to appoint him as an official, and invited him to serve as a censor in the palace. Later he entered the court and became a member of the Ministry of official affairs.
Zhang Jianfeng died in Xuzhou, and his son Zhang Xianyin was coerced by the state general to take charge of military affairs. The imperial edict ordered that those who were not afraid in the face of adversity be selected to announce the imperial decree to the Xuzhou army, so Li Yong was ordered to serve as Xuzhou's envoy. Li Yong went directly to his army, summoned the soldiers, conveyed the imperial decree, stated the interests and benefits, freed the imprisoned military commander from the shackles, and restored him to his original position. The evil party did not dare to disobey. After Zhang Huanyin submitted a petition calling himself "Bingmaliu", Li Yong believed that this was not an imperial edict and should not be given this title. He immediately asked him to remove it before accepting the petition. Later Li Yong was promoted to doctor in the Ministry of official affairs.
When Emperor Shunzong ascended to power, Li Yong was appointed as Yushi Zhongcheng, and was successively transferred to Jingzhao Yin and Shangshu Youcheng. At the beginning of Yuanhe (806-820), because there were many thieves in the capital, he was again selected as Jing Zhaoyin. He was able to capture traitors and restrain violent crimes, and his prestige was very high. Soon he visited the school's Minister of Etiquette, Fengxiang Yin, and Fengxiang Longyou Jiedushi. The town followed the old practice of appointing a general manager, mostly using military generals, and was known as the "Shengce Camp". At the beginning of receiving the order, he must go to the army to receive an audience. After Li Yong was ordered to do so, he stated in the imperial edict that this was not possible, and the edict canceled the number "Shengce Xingying" and only called it Fengxiang Longyou Jiedu. Soon after, he was transferred to guard Taiyuan, and then entered the court as Shangshu of the Ministry of punishment, concurrently as censor, and as envoy of salt and iron transport. In the winter of the fifth year of Yuanhe (810), he served as the governor of Yangzhou and the governor of Huainan. Li Yong had previously treated his subordinates in Fengxiang and Taiyuan towns with firmness and severity, and quickly changed the old system. This made people uneasy, so he soon changed it back. After arriving in Huainan for a few years, he was awarded the title of Inspector and Servant. His administration was strict and everything was in order, and the treasury and warehouses were fully stocked.
When Wang Shi conquered the Huaixi bandits, the Yunzhou bandits Li Shidao and the Huaixi bandits supported each other internally and externally. Li Yong sent more than 20,000 troops from Chu, Shou and other states to suppress the bandits respectively. The daily cost was very high, but he did not ask for help from the competent authorities. At that time, due to the mobilization of large armies, the state's supplies were insufficient. Emperor Xianzong ordered Cheng Yi, deputy envoy of Yantie, to take a post train to inform the various roads in the south of the Yangtze River to help fund the army's needs. Because the territory he ruled was rich and prosperous, Li Yong spent a lot of money on the treasury. Except for the one-year storage, all the money was donated to the court. From then on, the king's army no longer had to worry about shortages.
Previously Tutu Chengcui supervised the Huainan Army, and no one in power dared to disobey him. Li Yong was known for his uprightness and severity, and he showed respect to him without any disrespect. Tutu Chengcui returned to the court and recommended Li Yong as prime minister. In the twelfth year of Yuanhe (817), Li Yong was called to pay homage to his servant Tongping Zhangshi. Li Yong showed his authority when entering and leaving the capital, and he never regarded himself as an important official of the imperial court. Although he is older and has a powerful position, he is quite good at appeasing other townsmen. Every time he went to a farewell banquet, he would cry when he heard the banquet and said, "The post of prime minister is not what I am good at." His march was quite slow. When he reached the capital, he resigned and returned home due to illness. He neither paid homage to the emperor nor received any political duties. He finally resigned due to illness, and the imperial court appointed him as Minister of Household Affairs. Immediately, he was awarded the title of Zuopushe, the inspector, and was also a guest of the prince. He was assigned to serve in Luoyang, the eastern capital. Soon he retired as the prince and young master. He died in August of the 15th year of Yuanhe (820), and was given the posthumous title of "Su" to the crown prince Taibao.
Li Yong was strong and upright and did not hide himself. He was friendly with Yang Feng, Mu Zhi, Xu Mengrong and Wang Zhongshu, all of whom were willful and conceited. However, Li Yong was a serious and solemn official, strictly enforced the law, paid attention to political ethics, acted according to reason wherever he went, and was upright and decisive in dealing with personal matters. He guarded Yangzhou for seven years and enforced orders and prohibitions.
All matters of capture and killing were handed over to the military officials, and the staff did not dare to violate the prohibitions. Violators would be punished as illegal, so people were less dissatisfied.