| Year | Date | Historical Events |
| 1941 | Dec 1 | Keel laid down by the Electric Boat Co., Groton, CT. |
| 1942 | Aug 19 | Launched. |
| | Dec 2 | Commissioned with CDR. Sam D. Dealey in command.
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| 1943 | Mar 1 | Following shakedown off the East Coast, Harder sailed for Pearl Harbor, HI. |
| | Jun 7 | Harder departed Pearl Harbor, HI. on her 1st war patrol. |
| | Jun 22 | Cruising off the coast of Japan, Harder worked her way inside a picket line and sighted her first target. She made a radar approach on the surface and fired 4 torpedoes at the two ship convoy, sinking the Sagara Maru. |
| | Jul 7 | Harder returned to Midway Island. |
| | Aug 24 | Harder began her 2nd war patrol from Pearl Harbor, and, after touching at Midway, she headed for the Japanese coast. |
| | Sep 9 | While patrolling of Honshu, Harder attacked and sank the Koyo Maru and later that night ran by an escort ship at a range of 1,200 yards without being detected. |
| | Sep 11 | Harder encountered a convoy. After running ahead to improve her firing position, she sank the cargo ship Yoko Maru with a spread of 3 torpedoes. |
| | Sep 13 | Harder sighted two more ships, but she was forced down by enemy planes while firing torpedoes. Escorts kept the submarine down with a severe depth charge attack which lasted for over 2 days and almost exhausted her batteries. |
| | Sep 19 | Harder detected her next target. A torpedo sent the Kachisan Maru to the bottom almost immediately. |
| | Sep 23 | Harder continued to find good targets. She sank a 4,500 ton freighter, Kowa Maru, and a 5,800 ton tanker, Daishin Maru, off Nagoya Bay. |
| | Sep 28 | Her torpedoes expended, Harder turned Eastward. |
| | Sep 29 | Harder shot up 2 armed trawlers. |
| | Oct 4 | Harder touched at Midway Island. |
| | Oct 8 | Harder arrived at Pearl Harbor, HI. |
| | Oct 30 | For her 3rd war patrol Harder teamed with Snook and Pargo to form a deadly and coordinated attack group. Departing for the Marianas Islands. |
| | Nov 12 | Harder encountered a target. Promptly dispatching this one, she surfaced and sighted a trawler-escort damaged by the explosion of one of her own depth charges. Submerging again until sunset, the submarine sank the damaged ship with gunfire. |
| | Nov 20 | Sighting three marus, she radioed her companions and closed for attack. Harder fired 6 torpedoes at 2 ships, sinking the Udo Maru. 2 more torpedoes finished the Hokho Maru. |
| | Nov 30 | Harder returned to Pearl Harbor,HI., then sailed to the Mare Island Naval Shipyard, Vallejo, CA. for overhaul.
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| 1944 | Feb 27 | Returning to action in the Pacific, Harder reached Pearl Harbor, HI. |
| | Mar 16 | Harder departed on her 4th war patrol with Seahorse. She headed for the Western Carolines, where she was assigned duty as lifeguard ship for downed aviators. |
| | Apr 1 | Harder rescued an injured pilot awaiting rescue from the beach of a small enemy held island West or Woleai. |
| | Apr 13 | An enemy plane sighted Harder North of the Western Carolines and reported her position to Ikazuchi, a patrolling destroyer. As the enemy ship closed to within 900 yards, Harder fired a spread of torpedoes that sank the attacker within 5 minutes. |
| | Apr 17 | Harder spotted a merchant ship escorted by destroyers. Firing 4 torpedoes, she sank the 7,000 ton Matsue Maru and damaged one of the escorts. |
| | May 3 | Harder returned to Fremantle, Ausatralia from this highly varied and successful patrol |
| | May 26 | Assigned the area around the Japanese fleet anchorage at Tawi-Tawi, Harder departed Fremantle, Australia on her 5th war patrol with Redfin and headed for the Celebes Sea.
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| | Jun 6 | Harder encountered a convoy of 3 tankers and 2 destroyers. As one of the destroyers turned to attack, Harder submerged, fired 3 torpedoes at a range of 1,100 yards. 2 struck the Minatuski and exploded. The destroyer sank within 5 minutes. |
| | Jun 7 | Harder fired 3 torpedoes at a destroyer at short range, and 2 of them struck amidships, one detonating the ship's magazine with a tremendous explosion. Halyanami sank a minute later. |
| | Jun 8 | Harder transited the Sibutu Passage after dark and steamed to the Northeast Coast of Borneo. There on the night of 8 June she picked up 6 British coast watchers, and early next day she headed once more for Sibutu Passage.
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| | Jun 8 | Harder sighted two enemy destroyers. After submerging, she made an undetected approach and at 1,000 yards fired four torpedoes, sinking both ships. |
| | Jun 10 | Harder sighted a large Japanese task force, including 3 battleships and 4 cruisers with screening destroyers. As the range closed to 1,500 yards, she fired 3 torpedoes on a "down the throat" shot, and sank one of the escorting destoyers. |
| | Jun 21 | Harder steamed to Darwin, Australia for additional torpedoes. |
| | Jul 3 | Harder ended the patrol at Darwin, Australia. |
| | Aug 5 | Harder, accompanied by Hake and Haddo, departed Fremantle, Australia for her 6th and last war patrol. |
| | Aug 21 | Harder and Haddo joined Ray, Guitarro and Raton in a coordinated attack against a convoy off Paluan Bay, Mindoro. The Japanese lost 4 passenger-cargo marus, possibly one by Harder.
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| | Aug 24 | Sunk by Japanese destroyer 24 Aug 1944. 79 men lost. CDR. Dealey, "a submariner's submariner," was posthumously awarded the Medal of Honor. Harder received six battle stars for World War II service. |