He entered the Government Central School, Hong Kong (中央書院), and Sun Yat-sen was his schoolmate. He was a member of the Furen Literary Society which advocated revolution against the Qing Dynasty. In 1895 Wen joined the Revive China Society founded by Sun. In 1897 he studied at the Imperial Tientsin University (天津北洋大學堂), after graduating, he became an English teacher of the Queen's College(皇仁書院, reformed from the Government Central School). Later he became a secretary for Feng Keyi (馮克伊) who engaged in the work for negotiating to United Kingdom.
In July 1900 Wen Tsung-yao participated in the Independence Army uprising (自立軍) which was organized by pr-reform leader Tang Caichang (唐才常), and Wen was appointed a representative for foreign affairs to Shanghai. In next month, Tang failed to rise in rebellion against Qing Dynasty and was executed. Wen escaped to Southern China and got positions under the Viceroy of Liangguang (兩廣總督). From 1903 to 1908, he successively held the positions of Chief of Foreign Affairs Bureau of Liangguang (兩廣洋務局局長), Director to the Telephone Administration of Guangdong, Director to the Military Cadets' Academy of Guangdong (廣東將辦學堂), etc. In 1904 he was sent to India as Deputy Envoy to negotiate with the British Government over the question of British trade in Tibet (英藏訂約副大臣) and a member of the Tang Shaoyi's party. In same August Wen returned to China, and became a secretary for foreign affairs to the Viceroy of Liangguang Cen Chunxuan.
In 1908 Wen Tsung-yao was appointed Deputy President reside in Tibet (駐藏參贊大臣) as the representative of Qing Dynasty. On that time, United Kingdom's influence to Dalai Lama XIII was strengthened. So Wen wanted to recover Qing's influence, and insisted that Qing's troops station at Tibet to Dalai Lama XIII. But Dalai Lama XIII had protested against Qing's troops entered to Tibet, he fled to India, and Qing declared dethroning him. Later Wen returned to Peking, he was appointed a Councillor of the Foreign Office.
In October 1911 Xinhai Revolution broke out, Wen Tsung-yao, Wu Tingfang and Zhang Jian declared their support for republicanism. After the Republic of China was established in 1912, Wen participated in the movement for political parties. In August 1912 he participated in the Song Jiaoren's Kuomintang where he was appointed a councilor. In December 1915 the National Protection War broke out, Wen joined the National Protection Army against Yuan Shikai. In May 1916 the Military Bureau(軍務院) was established, Wen was appointed Deputy Diplomatic Envoy.
In September 1917 Sun Yat-sen started the Constitutional Protection Movement, and established the Canton Militarist Government. Wen also participated in it, but he supported Cen Chunxuan who was in opposition to Sun. In May 1918 Sun lost the leadership in the Government, when the governmental System was transformed to 7-President System. As Cen got the position of Chief of the Presidents, the disappointed Sun resigned as the President. In April 1920 Wen was appointed Minister for Foreign Affairs by Cen, and in May, also got the position of President. But in November, Cen was defeated by Sun and Chen Jiongming's troops, Wen also retired and hid in Shanghai for over 10 years.
In February 1938 Wen Tsung-yao was contacted by the Japanese who were invading China, and started to organize the Puppet Government for Japan with Liang Hongzhi. In the next month, they established the Reformed Government of the Republic of China in Nanking, Wen was appointed Chief of the Legislative Yuan (立法院院長). In March 1940 the Wang Jingwei regime was established, Wen was appointed Chief of the Judicial Yuan (司法院院長), and successively held many important positions.
After Japan unconditionally surrendered and the Wang Jingwei regime collapsed, Wen Tsung-yao was arrested by the Nationalist Government in Shanghai on September 27, 1945. On July 8, he was sentenced to life imprisonment on the charge of treason (Hanjian).
Wen Tsung-yao died in prison in Nanking on November 30, 1947.