Tong Dawei was born in 1979 in Fushun, Liaoning Province. He joined the Shanghai Theater Academy in 1997 and graduated in 2001 with a Bachelor of Arts in Acting.
Tong first gained attention for his role in the romantic film I Love You (2002) by acclaimed director Zhang Yuan. He then starred in Jade Goddess of Mercy (2003), which was a huge hit with the audience in China and launched Tong into a household name. After the success of Jade Goddess of Mercy, none of Tong's performance struck a chord in the audience, till he starred in the youth drama Romantic Life (2006). His powerful performance in the series left a deep impression on the audiences, and Tong returned to the limelight once again.
Tong hit a new peak in his career with his most successful television series yet; Struggle (2007). Based on the popular novel by Shi Kang, Struggle gained unexpected acclaim and was seen as a breakthrough in Chinese TV production as it broke from the usual Chinese TV series focusing in traditional legends and series. Tong’s character, Lu Tao, reflected the rise in a new social class in modern China. The same year, he starred in Lost in Beijing which premiered at the Berlin Film Festival and earned Tong a Best New Actor nomination at the Busan Film Critics Awards. He released his debut vocal album titled Da Shi Jie Xiao Zuo Wei (A Small Action in a Big World) in 2007.
In 2008, Tong starred in war epic Red Cliff: Part II, directed by John Woo. The film was also shown at the 2008 Cannes Film Festival, bringing Tong onto the international platform for the first time. The same year, Tong joined the Chinese ensemble in the film The Founding of a Republic, a movie marking the 60th Anniversary of the People’s Republic of China.
In 2011, Tong starred in award-winning director Zhang Yimou's film The Flowers of War. Dealing with the sensitive issue of the Rape of Nanjing, Tong plays Major Lee, who died as a hero to save his lost friend during China's anti-Japanese war. In order to better portray the role, Tong underwent military-like training and lost 16 pounds. Zhang praised Tong’s performance, saying that he added an “intellectual temperament to his character” and said he continues to “break through and impress the audience.” He became the first Chinese actor to walk the red carpet of the Golden Globe Awards.
Tong received acclaim for his role as an artistic youth in Peter Chan's American Dreams in China (2013), and he won the Best Supporting Actor awards at the Changchun Film Festival and Hundred Flowers Award. This was followed by another role in Peter Chan film, the critically acclaimed Dearest (2014), based on a true story about child abduction. He also co-starred in John Woo's romantic epic The Crossing (2014), based on the true story of the Taiping steamer collision and follows six characters and their intertwining love stories in Taiwan and Shanghai during the 1930s.
Tong reunited with Dearest co-star Zhao Wei in the television series Tiger Mom (2015), which focuses on parenting and children education. Tong won Best Actor at the 17th Huading Awards for his performance.
In 2016, Tong was appointed UN Women National Goodwill Ambassador.
On 17 April 2008, Tong married Guan Yue (born 1979), a film and television actress. The wedding was held in the Hotel Sofitel Wanda, Beijing. On 26 August 2008, Guan Yue gave birth to their daughter.