Gao Yang was not well regarded as a child, as he was awkward in interpersonal skills and at times considered developmentally disabled, being unable to carry out many tasks common for children, though it appears that he feigned this to prevent suspicion of his elder brother.

It appeared that he was actually of fairly high capability in many areas, and once, when Gao Huan tried to test his children's intelligence by giving them tangled balls of yarn to untangle, Gao Yang took out his sword and sliced the ball open, stating that that was the only solution.

He then planned taking the throne himself, but at a meeting in 549 at the capital Yecheng (鄴城, in modern Handan, Hebei), with his officials Chen Yuankang (陳元康), Cui Jishu (崔季舒), and Yang Yin, to discuss the procedure for doing so, he was assassinated by his servant Lan Jing (蘭京), who was angry at his wrongful treatment.

Initially, Emperor Xiaojing, who had received rumors that Gao Cheng had died, thought he might have a chance to regain power.

In spring 550, Gao Yang had Emperor Xiaojing convey on him the greater title of Prince of Qi Commandery.

When Yuwen saw that Emperor Wenxuan's troops were well-organized, he sighed and stated, "Gao Huan is not yet dead."

In spring 552, Emperor Wenxuan himself led troops against the Kumo Xi tribe (in the upper Liao River drainage area) and achieved a great victory.

In winter 553, Khitan tribes were attacking Northern Qi's northern borders, and Emperor Wenxuan himself led troops to attack Khitan—and on this campaign, he was described as personally exposing himself to the dangers and contributing much personally to defeating the Khitan.

However, Northern Qi forces were defeated by the Liang general Hou Tian (侯瑱), and Xiao Tui returned to Yecheng.

Around the new year 554, the remnants of Rouran, which by that point was near its end, surrendered to Northern Qi to seek protection from Tujue attacks.

In spring 554, Emperor Wenxuan, assisted by the senior general Hulü Jin (斛律金) and his brother Gao Yan the Prince of Changshan, launched a major attack on the Shanhu (山胡) tribe (in modern Lüliang).

Many traditional historians, including Li Yanshou (李延壽), the author of the History of Northern Dynasties, and Sima Guang, the author of the Zizhi Tongjian, saw this battle as the turning point of Emperor Wenxuan's rule—that thereafter, he began to act violently and capriciously.

In late 554, Western Wei launched a major attack on Jiangling (江陵, in modern Jingzhou, Hubei), then the capital of Liang.

Emperor Wenxuan commissioned an army commanded by Gao Huan's cousin Gao Yue (高岳) the Prince of Qinghe to attack Western Wei's An Province (安州, roughly modern Xiaogan, Hubei) to try to relieve pressure from Jiangling, but by the time that Gao Yue arrived, Jiangling had already fallen, and Western Wei captured and then executed Emperor Yuan.

Emperor Wenxuan had other ideas, however, and he created Emperor Yuan's cousin Xiao Yuanming the Marquess of Zhenyang, whom Eastern Wei captured in 547 during Liang's attempt to aid Hou Jing's rebellion against Eastern Wei, emperor, commissioning his brother Gao Huàn (高渙, note tone difference with his father) the Prince of Shangdang to command an army to escort Xiao Yuanming back to Liang territory.

However, with several generals loyal to Wang Sengbian rising against Chen following Wang's death, Emperor Wenxuan's mind changed, particularly after two, Xu Sihui (徐嗣徽) and Ren Yue (任約) submitted to him, making a surprise attack on the near-Jiankang fortress Shitou and capturing it.

Emperor Wenxuan sent the general Xiao Gui (蕭軌) to reinforce Xu and Ren.

Chen agreed, and sent his nephew Chen Tanlang (陳曇朗), Emperor Jing's nephew Xiao Zhuang the Prince of Yongjia, and Wang Min (王珉), the son of the key official Wang Chong (王沖), to serve as hostages to Northern Qi, allowing Liu to withdraw.

In summer 556, Northern Qi forces were again south of the Yangtze, operating in Jiankang's vicinity, but they were stalemated against Liang troops, eventually defeated by Chen and his generals after they ran out of food.

After he sobered up, he realized how she had been injured, and he set a large fire, intending to jump in to die, causing her to have to grab him to save him.

When Gao Huan's concubine Erzhu Ying'e, the Princess Dowager of Pengcheng, refused, he killed her with his own hands.

Emperor Wenxuan also became homicidal when he drank, and he always wanted to kill people when he was drunk, mostly by dismemberment, but sometimes by burning or drowning.

[8] However, even in his erratic behavior, Emperor Wenxuan was still attentive to many important matters, and because of his harshness, his officials did not dare to be corrupt.

Further, Yang was a capable prime minister, and Emperor Wenxuan gave him full authorization to carry out laws properly.

In spring 558, Northern Qi troops escorted Xiao Zhuang to Wang's territory, and Wang declared Xiao Zhuang emperor, as a Northern Qi vassal, with his capital at Jiangxia (江夏, in modern Wuhan, Hubei).

By this point, Emperor Wenxuan's military campaigns and other wasteful behavior had caused the imperial treasury to be drained.

When Emperor Wenxuan became drunk, he would often state that he might eventually pass the throne to his brother Gao Yan, and he stopped stating as such only after urging by Yang and Wei Shou, who believed that his words were causing an unstabling effect in causing a doubt as to who would succeed him.

In particular, a man named Yuan Huangtou was flown off a tower strapped to a kite as part of an experiment of Emperor Wenxuan, in the first known case of human flight.