Enlisted in the cavalry - 6th Uhlan Regiment - in 1914 and was wounded on the Western Front.
He also served in 80th Fusilier Regiment.
Received his commission to Leutnant in February 1915.
By the end of 1915 Gontermann was transferred to the GAAS and in 1916 became a pilot and aerial observer with FA 25.
He graduated from fighter pilot training in November 1916 and shot down his first confirmed victory - a RAF FE 2b - on 14th November 1916.
Was posted to Jasta 5 in France in April 1917.
In April 1917 Gontermann was given command of Jasta 15, also in France.
Gontermann was a renowned barrage balloon buster claiming four in a few minutes in August 1917 and a personal total of 17, plus one unconfirmed which is counted in some accounts raising his total victories to 40..
He was killed on 30th October 1917, at Marle, SE of St. Quentin, France, when the wing of a new model Tri-Fokker DR1 he was testing crumpled in flight.
His last victory was on 2nd October 1917 when he shot down a Spad (model unknown).
Confirmed victories
| Observation balloons | 17 | |
| Caudron Frères | Caudron ? | 1 |
| Caudron Frères | Caudron R4 | 1 |
| Caudron Frères | Caudron R11 | 1 |
| Royal Aircraft Factory | RAF BE 2c | 1 |
| Royal Aircraft Factory | RAF FE 2b | 6 |
| Royal Aircraft Factory | RAF RE 8 | 1 |
| Socièté Anonyme des Etablissements, Nieuport | Nieuport ? | 1 |
| Société S.P.A.D. | Spad ? | 7 |
| Sopwith Aviation Co | Sopwith 1.1/2. Strutter. | 2 |
| Sopwith Aviation Co | Sopwith Triplane | 1 |
| Total | 39 |
