Sun Liang was born in 243, to Sun Quan and one of his favorite consorts, Consort Pan. As Sun Quan's youngest son, he was well-cared for by his father, who was very happy to have a son in his old age (61 at the time of Sun Liang's birth). He was also born into a palace atmosphere where officials were aligning themselves with either of his two older brothers who were fighting for supremacy -- Sun He the crown prince and Sun Ba (孫霸) the Prince of Lu, who had designs on the position. In 250, fed up with Prince Ba's constant attacks against Crown Prince He, Sun Quan inexplicably ordered Prince Ba to commit suicide and deposed Crown Prince He. At the urging of his daughter Sun Dahu (孫大虎), who had been involved with falsely accusing Crown Prince He and his mother Consort Wang of crimes and therefore wanted to see Crown Prince He removed, he created Prince Liang as the new crown prince. Princess Dahu then had Crown Prince Liang married to a grand niece of her husband Quan Cong (全琮). In 251, Sun Quan created Crown Prince Liang's mother Consort Pan empress.
In 252, Crown Prince Liang would lose both of his parents in rapid succession. Early that year, Empress Pan was murdered—but how she was murdered remains a controversy. Eastern Wu officials claimed that her servants, unable to stand her temper, strangled her while she was asleep, while a number of historians, including Hu Sanxing, the commentator to Sima Guang's Zizhi Tongjian, believed that top Eastern Wu officials were complicit, as they feared that she would seize power as empress dowager after Sun Quan's death. Later that year, Sun Quan died, and Crown Prince Liang succeeded to the throne.
Prior to his death, Sun Quan had selected Zhuge Jin's son Zhuge Ke as the regent for Sun Liang, at the endorsement of his trusted assistant Sun Jun (a great-grandson of his uncle Sun Jing (孫靜)). The people of the empire also greatly admired Zhuge Ke, as he was already known for his military and diplomatic successes involving the indigenous Baiyue and for his quick wit. However, Sun's only reservation—that Zhuge was arrogant and had overly high opinion of his own abilities—would turn out to be prophetic.
In 252, in light of Sun Quan's death, Cao Wei's regent Sima Shi made a major three-pronged attack against Eastern Wu. Zhuge's forces, however, were able to defeat the main Cao Wei force, inflicting heavy losses. Zhuge's reputation became even more established. In 253, he carried out a plan he had for a while—to gather up nearly all service-eligible young men of Eastern Wu to make a major attack against Cao Wei—despite opposition by a number of other officials. He further coordinated his attack with ally Shu Han's regent Jiang Wei. However, his strategy turned out to be faulty—he initially targeted Shouchun (壽春, in modern Lu'an, Anhui) but, on his way, changed his mind and attacked Hefei instead, despite the fact that Hefei's defenses were strong and intended to withstand major Eastern Wu attacks. Zhuge's forces became worn out by the long-term siege and suffered plagues—which Zhuge ignored. He eventually withdrew after Cao Wei reinforcements arrived, but instead of returning to the capital Jianye (modern Nanjing) to apologize for his erroneous strategies, he remained from the capital for some time and never apologized to the people for the heavy losses suffered.
When Zhuge eventually did return to Jianye, he further sternly tried to wipe out all dissent, punishing all those who disagreed with him. Ke further planned another attack against Cao Wei, disregarding the recent heavy losses the people had suffered and their resentment. Sun Jun decided that he had to kill Zhuge. He told Sun Liang that Zhuge was planning treason, and he set up a trap at the imperial feast for Zhuge. (How much the young emperor knew of Sun Jun's plans and whether he concurred is unclear; traditional historians implied that Sun Liang knew and concurred, but he was just 10 years old at this point.) During the middle of the feast, assassins that Sun Jun had arranged for killed Zhuge, and Sun Jun's forces then wiped out the Zhuge clan.
After Sun Jun killed Zhuge Ke, he quickly moved to consolidate his power. He initially, on the surface, shared power with the prime minister Teng Yin (滕胤), but he, with control of the military, soon became even more dictatorial than Zhuge. In particular, he falsely accused the former crown prince Sun He of conspiring with Zhuge, and forced Sun He to commit suicide. His autocratic actions led to a conspiracy between Sun Ying (孫英) the Marquess of Wu (the son of Sun Quan's first crown prince Sun Deng (孫登)) and the army officer Huan Lü (桓慮), but he discovered the plan in 254, and both Sun Ying and Huan were executed.
In 255, in the midst of Cao Wei's having to deal with a rebellion by Guanqiu Jian and Wen Qin (文欽), Eastern Wu forces, led by Sun Jun, tried to attack Cao Wei's border region, but withdrew after Sima Shi quickly put down the rebellion. (Wen and his troops did surrender to him after they were defeated.) Later that year, another plot against Sun Jun was discovered, and a large number of officers were executed, along with Sun Quan's daughter Sun Xiaohu (孫小虎), falsely implicated by her sister Princess Dahu.
In 256, Sun Jun, at Wen's urging, was planning an attack against Cao Wei, when he suddenly fell ill, and he commissioned his cousin Sun Chen to succeed him as regent and died soon after.
Sun Jun's death would precipitate a major confrontation. The general Lü Ju (呂據), who was set to lead the main force against Cao Wei, was angry that the autocratic Sun Jun appointed Sun Chen, who had not distinguished himself in any way. Lü openly called for Teng to become regent instead, and Teng agreed to act with him. Sun Chen struck back militarily, and his forces defeated Teng's and Lü's. Teng and his clan were executed, while Lü committed suicide. In light of his defeat of Teng and Lü, Sun Chen began to become extremely arrogant.
In 257, at the age of 14, Sun Liang began to personally handle some important matters of state. He established a personal guard corps, consisting of young men and officers with age similar to his, stating that he intended to grow up with them. He also sometimes questioned Sun Chen's decisions. Sun Chen began to be somewhat apprehensive of the young emperor.
Later that year, Cao Wei's general Zhuge Dan, believing that the Cao Wei regent Sima Zhao (Sima Shi's brother) was about to usurp the throne, declared a rebellion and requested Eastern Wu assistance. A small Eastern Wu detachment, led by Wen, quickly arrived to assist him, but Sun Chen led the main forces and chose to camp a long distance away from Shouchun, where Zhuge was being sieged by Sima, and did nothing. When Sun Chen instead ordered the general Zhu Yi to try to relieve Shouchun with tired and unfed troops, Zhu refused—and Sun Chen executed him, bringing anger from the people, who had admired Zhu's military skills and integrity. With Sun Chen unable to do anything, Zhuge's rebellion failed in 258, and Wen's troops became captives of Cao Wei.
Sun Chen knew that the people and the young emperor were both angry at him, and chose not to return to Jianye, but instead sent his confidants to be in charge of the capital's defenses. Sun Liang became angrier, and plotted with Princess Dahu, the general Liu Cheng (劉丞), his father-in-law Quan Shang (全尚), and his brother-in-law Quan Ji (全記), to have Sun Chen overthrown. However, Quan Shang did not keep the plot secret from his wife, who was Sun Chen's cousin, and she told Sun Chen. Sun Chen quickly captured Quan Shang and killed Liu, and then surrounded the palace and forced the other officials to agree to depose Sun Liang—falsely declaring to the people that Sun Liang had suffered psychosis. Sun Liang was demoted to the title of the Prince of Kuaiji.
Sun Chen then made Sun Liang's older brother Sun Xiu, the Prince of Langye, emperor. Several months later, Sun Xiu set a trap for Sun Chen and had him arrested and killed. However, Sun Liang's position in exile did not become any safer, as Sun Xiu deeply feared that there would be plots to return Sun Liang to the throne. In 260, there were rumors that Sun Liang would be emperor again, and Sun Liang's servant girls falsely accused him of employing witchcraft. Sun Xiu demoted Sun Liang to the title of the Marquess of Houguan, and sent him to his march (in modern Fuzhou, Fujian, then considered in deep wilderness). On the way, Sun Liang died—and while most historians believe that he committed suicide, an alternative theory is that Sun Xiu had him poisoned.