Johann Graf Salis-Seewis was born on the 8th of December 1862 in Karlsatdt in Croatia as the third child and eldest son of k.k. Hauptmann Gaudenz Graf Salis-Seewis and his wife Wilhelmine (Vranyczany von Dobrinovic). His father died in 1873 at the early age of 41. After attending the Gymnasium at Kremsmünster he became a cadet at the technical military academy in Vienna from which he was commissioned on the Kaiser's birthday, 18th of August 1883 as a Leutnant with assignment to the 2.Genieregiment (engineer regiment). He graduated from the infantry equitation courses at Budapest in 1883 and at Vienna in 1885.86 with very good success. He attended the course at the war school as an Oberleutnant and on graduation in 1890 was attached to the general staff corps and saw service with the infantry brigades at Josephstadt and at Salzburg. Promoted to Hauptmann in the general staff corps on the 1st of November 1893 he served as an instructor at the infantry cadet school at Preßburg until assuming an appointment in the intelligence section in the general staff at Vienna in October 1896. Remaining in the "Evidenzbureau" until May 1898 he then performed the obligatory duty with the troops as a company and battalion commander with the 82nd Hungarian infantry regiment in Gyulafehérvár. After the successful completion the so-called "Archangel" exam for promotion to major in the general staff he was promoted Major on the 1st of November 1899 and returned to general staff service as the chief of staff of the 28th infantry division in Laibach (Ljubljana) before returning to the intelligence section from 1901 to 1904. He was promoted Oberst on the 1st of November 1903.
From 1904 to 1906 he was assigned as a military advisor to the international commission in Macedonia in Skopje, Salonica and Istanbul. He was awarded the Order of the Iron Crown 3rd class in 1906 and on his return from this assignment he saw further service at troop duty with infantry regiments 86 in Budapest and 76 in Esztergom before assuming command of the famous Hungarian-Croatian Otocaner 79th infantry regiment Graf Jellačić in April 1908. The NCOs and men of the regiment were predominantly Croatian whereas the commissioned officers were about fifty percent German, twenty five percent Croatian and the remainder of various nationalities. The very popular regimental commander relinquished command in August 1911 and was appointed brigade commander of the 71st infantry brigade headquartered in Fiume to which his old regiment belonged. Promoted to Generalmajor on the 9th of May 1912 he would command this brigade at the outbreak of the First World War as part of Feldmarschalleutnant Claudius Czibulka's 36th infantry division within the XIII corps of General der Infanterie Adolf Freiherr Rhemen zu Barensfeld.
As a part of General der Infanterie Liborious Frank's 5th army, Salis-Seewis's brigade took part in the initial unsuccessful operations against Serbia; the forcing of the River Drina and the subsequent withdrawal. The second crossing of the Drina followed. This river with a width of from 200-500 yards and a depth of between 2 and 6 metres was an extremely difficult operation. He took part in the operations in the Macva, the successful attack at Banova Polje, Vrbocav, Radenkovic and the seven day battle of Sabac-Sjesnice. During that very hot trying summer the 5th army lost 600 officers and 22,000 NCOs and men from it's initial complement of some 80,000. In spite of the failings of the senior command, Generalmajor Graf Salis-Seewis performed well and was appointed as commander of the 42nd Royal Hungarian Landwehr (Honvéd) infantry division on the 11th of November 1914. He led this division in the second Serbian offensive always from the front which ended in the defence of the Kolubar line after which his division was withdrawn for rest and re-fitting. On Erzherzog Eugen's assumption to the command of the southern front he voluntarily made available the entire XIII corps to General der Kavallerie Pflanzer-Baltin's army group fighting in the Carpathian mountains and so Salis-Seewis with his division moved to the Galician front. XIII corps now fought in the grueling conditions of a Carpathian winter and in February penetrated into Delatyn and to the railway line to Stanisalau. Salis-Seewis was promoted Feldmarschalleutnant on the 15th of February and was awarded the Order of the Iron Crown 2nd class with war decoration.
At the end of March 1915 Salis's division was placed under the command of the German General der Kavallerie Marschall which alongside two other Austro-Hungarian divisions and a German division was in position from the River Pruth at Czernowitz to the River Dniester. Following a Russian flank attack the troops of Salis's 42nd division were compelled to withdraw and the Russians were able to cross the Dniester. Despite a counter-attack by half of the 42nd and an Austro-Hungarian cavalry division the situation could not be immediately restored. General Salis' division was thereafter used wherever the situation was most critical and following reinforcement of the front by troops from Carinthian and Steiermark, Pflanzer-Baltin was able to counter-attack and once again secure the left bank of the Pruth. Graf Salis remained in command of the excellent Domobran division until the middle of April when he went on a months leave. Returning from leave he finally handed over command to Feldmarschalleutnant Anton Liposcak in mid June 1915 and until October the general was unemployed. Graf Salis was appointed the military governor of Vienna and 10th of November 1915 he took up his new post. The military governorship of Vienna however was relatively short-lived as on the 7th of January 1916 having been appointed as a Geheimer Rat (privy councillor), he assumed a new appointment, that of the military general governor of Serbia. On the 1st of January 1916 the military general government of Serbia had been formed and was responsible for the administration of 23,880 square kilometres and over a million and a half inhabitants. With the assistance of his capable chief of staff, Oberstleutnant Otto Gellinek would remain in Serbia until July until he was replaced by his former corps commander, General der Infanterie Adolf Freiherr Rhemen zu Barensfeld in July.
Graf Salis was then appointed as vice president of the supreme military court and from June 1917 until his assumption of the command of the 92nd infantry division in October 1917 after requesting further front line service he was the acting head of that organization. He led his division in Rumania until further appointed as the corps commander of the so-called Generalkommando Rumänien headquartered at Pitesti at which post he was awarded the Military Merit Cross 2nd class with war decoration and swords. Graf Salis's last appointment was as commander of the 16th General Command which he led until the war's end in the Rumanian theatre being promoted to Feldzeugmeister on the 11th of November 1918 which in fact was the final promotion to this rank. He retired on the 1st of January 1919 with a pension of 16,000 crowns and elected to live in Croatia. The General died in Zagreb on the 24th of October 1940.