Peng began his career when he was cast as in The White Paper of Love by director Yang Daqing. The drama is adapted from the Japanese manga series Asunaro Hakusho, written by Fumi Saimon. In 2003, he took on his first leading role in the Taiwanese drama Scent of Love, which tells the story of two star-crossed lovers who transcend life and death to find one another in their many reincarnations.
In 2005, he starred in the idol drama When Dolphin Met Cat, portraying a autistic youth. To prepare himself for the filming, Peng took one month to learn how to interact with dolphins from a trained instructor. He then starred in Chinese xianxia drama Chinese Paladin, which was extremely popular during its run and led to increased recognition for him in the Mainland.
Thereafter, Peng made his big screen debut in the movie Exit No.6 (2006), directed by Yu-Hsien Lin. Since then, he was attracted to the film industry. In 2007, Peng was nominated as Best New Actor at the 44th Golden Horse Film Festival and Awards for his performance in My DNA Says I Love You.
In 2009, Peng was involved in a contract dispute lawsuit against his former manager, reaching the nadir of his career. However during this period, Peng starred in the movie Hear Me, directed by Fen-Fen Cheng, about a delivery boy who falls for a hearing impaired girl and communicates with her using sign language. The film was released a week prior to the opening of the 21st Summer Deaflympics, and became the highest grossing locally produced movie at Taiwan's box office.
After winning the lawsuit in 2010, he released his debut EP titled It Has To Be You, which featured 5 songs under the management of Avex Group.
The same year, he starred as the male lead in the movie Close to You. In order to portray his role as a boxer, Peng trained for three months prior to filming. He was nominated in the Best Actor category at the 2nd Macau International Movie Festival for his performance.
Peng achieved breakthrough in 2011 teen film Jump Ashin!, directed by Yu-Hsien Lin. He reportedly trained eight months to portray an athlete. The film was a critical and commercial success. Peng earned nominations as Best Actor at the 48th Golden Horse Film Festival and 13th Taipei Film Festival, which marked the turning point of his career.
Thereafter, he starred in romance films Love You You and Love; police thriller Cold War; kungfu comedy Tai Chi 0 and Tai Chi Hero; showcasing his versatility.
In 2013, Peng starred in action film Unbeatable, playing a young man who wishes to learn Mixed martial arts. Unbeatable was the highest grossing local production at the Hong Kong box office, and received positive reviews. Peng's realistic portrayal of a MMA fighter earned him nominations as Best Supporting Actor at the 33rd Hong Kong Film Award and 50th Golden Horse Film Festival and Awards. The same year, Peng starred in romantic comedy A Wedding Invitation alongside Bai Baihe. The film earned nearly 200 million yuan ($32 million) in China, making it the highest-grossing Chinese-South Korean production.
In 2014, Peng was cast as Wong Fei-hung in Rise of the Legend, the latest film about the iconic Kung-Fu master. He reportedly practiced 10 hours of martial arts every day to prepare for the role. Peng was nominated in the Best Actor category at the 34th Hong Kong Film Award. The same year, he starred in historical drama Sound of the Desert and coming-of-age film Fleet of Time, which were both commercial successes. Peng's achievements in both the film and television industry brought his career to a new height.
In 2015, Peng played a professional cyclist in sports film To the Fore. The film was selected to represent Hong Kong in the best foreign-language film category at the 88th Academy Awards. Peng was also appointed the first Chinese Goodwill Ambassador of the 2015 Tour de France due to his healthy image. The same year, Peng starred alongside Shu Qi in romance film The Last Women Standing.
Peng achieved another breakthrough in 2016 with the film Operation Mekong, where he portrayed a hardcore undercover agent along with veteran actor Zhang Hanyu. The film not only received critical acclaim, but is also the highest grossing Chinese cop film to date. He also starred in romance film Run for Love alongside Zhang Ziyi, police thriller Cold War 2 as an antagonist, war epic Call of Heroes and Zhang Yimou's historical epic The Great Wall.
In 2017, Peng co-starred in Han Han's film Duckweed alongside Deng Chao and Zanilia Zhao. The sleeper hit gained commercial and critical success. He then starred in war film Our Time Will Come directed by Ann Hui, which won critical acclaim and became Ann's highest-grossing film. Peng then headlined his first film, fantasy epic Wu Kong where he played the title character.