Dominik became the protégé of Hauptmann Kurt von Morgen, who served in the same regiment and had undertaken two research journeys to central Cameroon in 1889 and from 1890 to 1891.

In Cairo, he hired Sudanese mercenaries for the new Schutztruppe and participated in the first military campaign against the Abo, northwest of the port city of Douala.

He went on to take part in the Vute-Adamawa expedition as company leader under the leadership of the Schutztruppe's commander, Oltwig von Kamptz.

Dominik returned to Germany in 1900, leaving again the next year to serve as special envoy of the government to the Kamerun colony.

However, plans for a peaceful solution for the conflict were ruined when Hauptmann Rudolf Cramer von Clausbruch [de], commander of Joko [de] military station, ignored orders from Governor Jesko von Puttkamer and began a military occupation of Adamawa.

In 1909, the Maka of the upper Nyong River rebelled; Dominik crushed the unrest with the aid of Hauptmann Marschner from the Schutztruppe.

Despite their apologetic character, Dominik's two publications are today a valuable source of information on the history of Cameroon and its people.