The designer of the flag was professor Arne E. Holm, whose proposal was approved by the municipal council in 1989, and confirmed by royal order the same year.

It is earliest preserved in the seal of the church chapter of Trondheim used in the 16th century.

The idea of the rose as a symbol of Trondheim may originally have come into being because of a misinterpretation of the last syllable of the city's old name Nidaros.

The flower has been so closely connected to Trondheim that the Norwegian heraldic authority denied other municipalities the use of it in their coats of arms.

The flag of Trondheim has been highlighted as an example of a good city flag design by Roman Mars in his radio show "99% invisible", a radio show focused on design and architecture.