Nog was a Ferengi male, the son of Rom and Prinadora, and the nephew of Quark. He was the first Ferengi to enter Starfleet, and served aboard Deep Space 9 and the USS Defiant during many of the most important battles of the Dominion War.

On the station he met Jake Sisko, Commander Sisko's son. Because there were only a few children on board DS9, Jake and Nog spent a lot of time together and soon became close friends and would have many adventures and misadventures together.
(DS9: "A Man Alone", "The Nagus")

In 2370, Nog was evacuated for a short time from DS9 because of the threat of Bajoran incursion.
(DS9: "The Siege")

He also was attacked by Tumak when he sprayed some foul-smelling fluid on him.
(DS9: "Sanctuary")

In 2372, Nog's uncle Quark received a shuttle from his cousin Gaila and he decided to bring Nog, accompanied by his father, to Earth so he could enter Starfleet Academy.
(DS9: "Little Green Men")

Nog fought in the Second Battle of Deep Space 9 when the Dominion and Cardassian forces captured the station.
(DS9: "Call to Arms")

In 2374, after the outbreak of the war between the Federation and the Dominion, Nog took part in the raid to destroy the major production facility of ketracel-white inside Dominion territory.
(DS9: "A Time to Stand")

In the latter part of this year he was promoted to ensign. This is after just two years as a cadet, as opposed to the normal four. He took part in the battle to retake Deep Space 9.
(DS9: "Favor the Bold")

When the USS Defiant was captured by the Jem'Hadar, he helped retake the ship. He pretended he was fixing the warp drive that had been damaged in the attack. But this was a delaying action until they could be rescued.
(DS9: "One Little Ship", "Profit and Lace")

During the siege of AR-558, Nog performed well as an advance scout, using his superb Ferengi hearing to identify a large column of advancing Jem'Hadar when tricorder scans were ineffective due to a Jem'Hadar jamming signal. It was during this action that he lost his leg after fierce fighting with Jem'Hadar soldiers, who outnumbered the Starfleet forces three-to-one. When Nog was recuperating in a makeshift infirmary, a Jem'Hadar burst in but Quark managed to kill him, saving his nephew from certain death. In part because of Nog's actions, and those of his fellow troops, the Federation was able to hold the planet and the vital Dominion communication array there.
(DS9: "The Siege of AR-558")

When he returned to DS9, Nog was still recovering from his injuries and, although his leg was replaced by a biosynthetic one, he was still struggling to cope emotionally and physically with his wound. Because he did not want to be helped by anyone he took his medical leave in one of his uncle's holosuites, hiding in the 1962 Las Vegas club of singer Vic Fontaine. During this time, Vic affectionately nicknamed Nog "Noggles". Later, when Nog found Jake and his date Kesha in Vic's lounge, he was upset and in an angry outburst, he punched Jake, whereupon Vic threw Nog out of his club. Ezri Dax visited Nog to persuade him to leave the holosuite, but he refused. He even threatened to resign his Starfleet commission if she tried to make him leave. While Ezri observed him, she noticed that he had made progress. He no longer seemed to limp or need to use his cane. When his father and Leeta visited him in the club, he was even happy. Congratulating Vic with his accomplishments with regards to Nog, Ezri let him know it was time for Nog to leave the holosuite. When Vic told Nog he had to leave he protested, but to no avail, considering that Vic resorted to ending the program on his own and resisted it being reactivated. In the end, Vic convinced Nog that it was better for him to leave and rejoin the real world. Nog thanked him, and to show his gratitude, made arrangements with his uncle Quark to keep the holoprogram running permanently.
(DS9: "It's Only a Paper Moon")

Nog took part in the Second Battle of Chin'toka as a member of the Defiant crew.
(DS9: "The Changing Face of Evil")

when the Dominion War ended in 2375, Nog was promoted to lieutenant junior grade in one of Benjamin Sisko's last official acts as the commanding officer of DS9.
(DS9: "What You Leave Behind")