He was an early advocate for vegetarianism and veganism, and various other causes including abolitionism, anti-vaccination, temperance, women's suffrage and the peace movement.

A prosperous merchant, Dornbusch operated a business on Threadneedle Street and published The Floating Cargoes Daily List from 1854 to 1873.

[1] Dornbusch became a vegan in 1843, "partaking neither of fish, flesh, fowl, butter, milk, cheese, or eggs, and abstaining also from the use of tea, coffee, intoxicating drinks, salt, and tobacco".

[6] Dornbusch served as treasurer of the Stop-the-War League[5] and was a member of the general committee of the Emancipation Society, along with John Stuart Mill.

[4] Dornbusch was also involved with the Anti-Compulsory Vaccination League[10] and the National Society for Women's Suffrage, serving on the central committee from 1871 to 1872.

[6] In December 1846, Dornbusch married Johanna Wilhelmine Amalie Siemers, the daughter of a Hamburg merchant.