Promoted to lieutenant, junior grade, on 1 December 1913, he served aboard the destroyer Kikutsuki before transferring to the protected cruiser Chikuma on 27 May 1914.

Chikuma was part of the Imperial Japanese Navy squadron which gave chase to the German East Asia Squadron in 1914, then joined the armored cruisers Ibuki and Nisshin in hunting for the Imperial German Navy light cruiser SMS Emden, which was raiding Allied shipping in the Indian Ocean.

As a result, Hosogaya was relieved of command on 31 March 1943, and Kawase was placed in charge of the 5th Fleet and the Northern Area Force the following day with his headquarters at Paramushiro in the Kurile Islands.

Kawase put to sea from Paramushiro in his flagship, the heavy cruiser Maya, accompanied by a destroyer to rendezvous with the seaplane tender Kimikawa Maru, which was part of a small convoy carrying floatplanes to Attu.

However, Kawase had received reports that the U.S. Navy task force of 40 ships included three battleships and an aircraft carrier, and – not knowing that the American ships were temporarily out of ammunition after providing gunfire support to American troops ashore – he ordered his outnumbered and outgunned task force to loiter 300 nautical miles (556 km; 345 mi) west of Attu, hoping for a break that would allow him to get the reinforcements through.

On 28 May, Kawase informed Yamasaki that the 5th Fleet's submarine force had been recalled because of losses it had suffered to U.S. Navy destroyers, and Attu fell to the Americans on 30 May after the almost complete annihilation of the isolated Japanese garrison.

United States Army Air Forces (USAAF) aircraft soon began to operate from Attu; USAAF aircraft staging through Attu even made the first airstrike against Paramushiro on 18 July 1943, causing a startled Kawase to wheel his office chair to a window to see what was happening after a string of bombs detonated on a taxiway.

Imperial General Headquarters wanted the Kiska garrison withdrawn so that its troops could be employed in the defense of the Kurile Islands, and ordered Kawase to use his submarines to evacuate them.

"[10] He decided to gamble on a bold move: Running the American blockade by steaming a surface force to Kiska in what the Japanese designated as Operation Ke-Go.

With Kawase aboard Tama as an observer, the force departed Paramushiro on 21 July 1943 bound for a point 500 nautical miles (926 km; 575 mi) south of Kiska, where it would refuel and await fog cover for its run to the island.

[11] Receiving reports on 25 July that a U.S. Navy PBY Catalina flying boat had made radar contact on Japanese ships operating southwest of Attu, a force of U.S. Navy battleships, cruisers, and destroyers set off in search of it and on 26 July opened fire on phantom radar contacts ("pips") south of Amchitka in what became known as the "Battle of the Pips."

Giving up on awaiting the arrival of a storm before entering port, Kawase ordered the ships forward on 28 July to make the final run in to Kiska.

While Tama with Kawase on board waited 20 nautical miles (37 km; 23 mi) offshore to cover the operation, Kimura and the remaining ships entered Kiska Harbor, took aboard all 5,183 Japanese troops in an hour, rendezvoused with Tama and Kawase, and made a high-speed dash back out of the area, arriving at Paramushiro on 31 July-1 August 1943.

In fact, American and Canadian forces earmarked for the invasion of Kiska were so unaware of the Japanese evacuation that they continued a heavy air and naval bombardment of the island and dropped propaganda leaflets there until their troops stormed ashore in Operation Cottage on 15 August 1943 expecting heavy combat with the Japanese – only to find the island uninhabited.

[18] Kawase began another tour of duty with the Navy General Staff in Tokyo on 15 February 1944, then moved briefly to the position of assistant chief of staff of the Southwest Area Fleet – which coordinated naval, air, and ground forces for the occupation and defense of the Philippine Islands, French Indochina, the Malay Peninsula, and the Netherlands East Indies – on 5 June 1944.