He was frequently under pressure from the government, which was displeased with the pacifist's lyrics of such songs as Ngủ đi con (Lullaby, about a mother grieving for her soldier son).

Before April 30, 1975, Trịnh Công Sơn went on the radio in Saigon to sing the song "Joining Hands/Circle of Unity" ("Nối vòng tay lớn") about the dream of national reconciliation between the North and the South, which he had written in 1968.

On the afternoon of April 30, following Dương Văn Minh's proclamation of surrender, Trinh went on the radio to say that the national dream had been realized and that liberation had been achieved.

[6] Khánh Ly helped popularize Trịnh Công Sơn's music in the early years, and they often performed together at South Vietnam University campuses.

[10] In the song "Mother's Legacy" (Gia tài của mẹ), Trinh sings about the Vietnamese experience of the Vietnam War:[11] He laments that the 1,000 years of Vietnam's subjugation to Chinese imperial rule, the 100 years of subjugation to French colonial rule, and the ongoing civil war, together have left a sad legacy of graveyards, parched fields and burning houses.

He urges the children of Vietnam to remain true to their Vietnamese identity and overcome the dividing hatred, put an end to internecine fighting and the destruction of the country.

A rock music concert event titled Nối Vòng Tay Lớn ("The Great Circle of Vietnam"); the name of a popular patriotic anti-war song by Trịnh Công Sơn, was officially promoted and held in Hồ Chí Minh City ostensibly as a memorial to Trịnh, and featuring various Vietnamese rock bands and artists, had officially taken place for the first time on 22 April 2022.

Other songs, additionally carry philosophical messages from a man to his lover: "Cỏ xót xa đưa", "Gọi tên bốn mùa", "Mưa hồng".