Grizmallt, a planet situated within the Core Worlds, was home to Humans known as the Grizmallti. Around 3950 BBY, Queen Elsinoré den Tasia ascended to the throne of Grizmallt, ushering in an age marked by exploration and the establishment of colonies. Despite numerous unsuccessful ventures, Grizmallti colonists successfully settled on various planets across the galaxy, notably including eight planets within the Renatasia system and the world of Nam Chorios. Approximately around 3900 BBY, Grizmallt became embroiled in a civil war, prompting Tasia to support a final refugee expedition that ultimately led to the Human colonization of Naboo.
During the final century of the Galactic Republic, Grizmallt boasted one of the galaxy's most extensive engineering complexes. Following the commencement of the Clone Wars, the Commissars of Grizmallt initiated operations aimed at enhancing their competitive edge against Kuat Drive Yards. Sometime between 21 BBY and 18 BBY, Queen Apailana and Senator Jar Jar Binks from Naboo conducted an official state visit to Grizmallt. Binks inadvertently caused a memorable blunder due to the disparities between the Royal Script of Grizmallt and the Naboo Futhark, which had evolved from the former writing system. Grizmallt later functioned as an Imperial fortified planet, but in 6 ABY, the planet surrendered to the New Republic fleet commanded by Admiral Gial Ackbar.
Grizmallt was a terrestrial planet situated in the Grizmallt system, located within the Core Worlds. It was positioned along the Perlemian Trade Route hyperlane, linking it to the Alsakan and Axum systems while also delineating the boundaries between the regions known as the Northern Dependencies and the Slice—specifically, the Arrowhead. Reportedly, a unique subspecies of nerf was discovered there, exhibiting minimal resemblance to other members of the same species. It was hypothesized that the differences in neck length and body structure compared to common nerfs stemmed from millennia of reaching for foliage and berries on elevated tree branches.

During the initial stages of the Alsakan Conflicts, a series of wars that erupted around 17,018 BBY between the Galactic Republic's capital planet Coruscant, the world of Alsakan, and their respective allies, Grizmallt sided with Alsakan. The Grizmallti at one point colonized the Outer Rim Territories planet Nam Chorios, which later transformed into a prison colony under the rule of the Grissmath Dynasty. Around 4000 BBY, the Grizmallti discovered a Mid Rim planet in the southern galactic quadrant, which they named Nabu after one of their primary deities. Grizmallti aristocrats frequented Nabu as a vacation destination, prompting the world's natives, the Gungans, to retreat into the swamps to avoid the influx of newcomers.
Around 3950 BBY, Elsinoré den Tasia assumed the role of queen of Grizmallt, inaugurating a new era of exploration and colonization. During Tasia's reign, the Palazzo Reina was constructed, with inscriptions inside it employing the Royal Script of Grizmallt, a writing system based on oval shapes. In 3950 BBY, Tasia sponsored the colonization of the Renatasia system, resulting in the establishment of settlements on eight planets within the system, although they eventually became isolated from the rest of the galaxy. While the Grizmallti colonized numerous worlds, the majority of their colonization endeavors ended in failure as colony ships were destroyed or lost. Furthermore, Grizmallt was plunged into a civil war around 3900 BBY.

Around that time, Queen Tasia, nearing her death, sponsored a final expedition destined for the southern galactic quadrant. This expedition comprised Human Grizmallti refugees seeking fortune and glory, traveling aboard three colony ships: the Beneficent Tasia and its support starships, Constant and Mother Vima. A renowned Jedi Master blessed the expedition, which was led by the scout Kwilaan. After their departure from Grizmallt, Tasia passed away, hoping for the expedition's safe arrival in her final moments. Contact with the Beneficent Tasia was lost shortly afterward, leading the Grizmallti to presume the ships were lost; however, they had merely sustained damage and were unable to communicate due to the perils of space.
It was later discovered that the expedition had survived and that the refugees had colonized Nabu. The planet's name was subsequently changed to Naboo, and the descendants of the colonists became known as the Naboo people, who developed a handwritten script called Futhark derived from the Royal Script of Grizmallt. A symbol associated with Grizmallt also became the emblem of the Royal House of Naboo. Around 3642 BBY, Moff Tyrak of the Sith Empire enlisted the services of the best surgeon on Grizmallt to surgically alter his hair to be gold, claiming it was a million-credit procedure.
In the Galactic Republic's last century, Grizmallt housed one of the galaxy's most substantial heavy engineering facilities, rivaling only Kuat Drive Yards and Rendili Stardrive. The Naboo continued to revere Tasia's memory thousands of years after her death, with some individuals paying tribute through their dress style and facial decorations, asserting an unbroken lineage to her. This fact was acknowledged by Muun financier Larsh Hill during a meeting on Naboo between 67 BBY and 65 BBY. During the Invasion of Naboo by the Trade Federation in 32 BBY, the handmaidens of Naboo's Queen Amidala donned dark purple robes adorned with a symbol linked to Grizmallt.
In 22 BBY, Senator Tashrikam represented Grizmallt in the Republic's Galactic Senate. Following Supreme Chancellor Palpatine's establishment of the Loyalist Committee, a group intended to address the growing threat of the Confederacy of Independent Systems diplomatically, Tashrikam characterized the committee as a political ploy to save face, while also noting that Palpatine was seeking guidance by turning to more proactive senators. Tashrikam's remarks were documented in the 13:3:28 edition of the HoloNet News CoCo District Edition.

Later that year, tensions between the Republic and the Separatists escalated into the galaxy-spanning Clone Wars at the Battle of Geonosis, which resulted in a Republic victory due to the emergence of the new Grand Army of the Republic that utilized Acclamator-class assault ships designed by Kuat Drive Yards. Shortly thereafter, the Commissars of Grizmallt tasked industrial spies and starship designers with diminishing Kuat Drive Yards' competitive advantage in securing new contracts for military vessels.
In 21 BBY, the Festival of Light was celebrated on Naboo to commemorate the planet's entry into the Republic, and the festivities included a holographic display of one of the Grizmallti colony ships. Between 21 BBY and 18 BBY, Queen Apailana of Naboo conducted a state visit to Grizmallt alongside Gungan senator Jar Jar Binks. Apailana and Binks toured the Palazzo Reina, where the senator inadvertently caused a memorable incident by misinterpreting the name of the building's Heroine Hall as "Hero in Hell" due to the slight variations between the Royal Script of Grizmallt and Naboo Futhark.
In 19 BBY, the Republic was transformed into the Galactic Empire, under which Grizmallt became a fortress world. Sometime after the Battle of Yavin, fought between the Empire and the Rebel Alliance as part of the Galactic Civil War, an individual developed a secret recipe for Slipthroat Grizmallt Liquor and embarked on a lengthy journey to deliver it, during which all of their companions perished.
Nearing the end of their journey, the individual encountered a spacer and requested their assistance in reaching their destination, without revealing the nature of their cargo. After the spacer agreed and escorted them to safety, the individual disclosed that they were carrying the secret formula.

Later in the Galactic Civil War, the Rebel Alliance evolved into the New Republic and captured Coruscant in 6 ABY. Along with Alsakan, Wukkar, and numerous other worlds, Grizmallt surrendered to the fleet of the New Republic Admiral Gial Ackbar with minimal resistance. Following the Swarm War in 36 ABY, Grizmallt was referenced in several academic works. The existence of the nerf subspecies on Grizmallt was documented in The New Essential Guide to Alien Species, compiled from the notes of Senior Anthropologist Mammon Hoole. The planet's role in the colonization of Naboo was recorded in a document by the Historical Council of the Galactic Federation of Free Alliances, and the connection between the Royal Script of Grizmallt and Naboo Futhark, along with the events of Binks' visit, was documented by Doctor Milanda Vorgan in the academic text "The Written Word: A Brief Introduction to the Writing Systems of Galactic Basic" in 38 ABY.
Grizmallt was a densely populated world, inhabited by Humans known as the Grizmallti, who employed a writing system called the Royal Script of Grizmallt. The planet operated under a monarchial government led by Queen Tasia and was represented in the Galactic Senate around the time of the Separatist Crisis. The commissars of Grizmallt were a group active during the Clone Wars, playing a role in coordinating starship designs for the Republic.
Grizmallt housed one of the galaxy's largest heavy engineering facilities. During Tasia's reign, the Palazzo Reina was constructed, which included Heroine Hall. The capital of Grizmallt featured an Old Quarter, which, like the Palazzo Reina and other structures from Tasia's reign, displayed signage written in the Royal Script of Grizmallt.

The Dark Empire Sourcebook, authored by Michael Allen Horne and published by West End Games in 1993, marked the first mention of Grizmallt. In Star Wars Galaxies: An Empire Divided Quick Reference Guide, a companion to the video game Star Wars Galaxies published in 2003, the planet's name was misspelled as "Grizmalit," an error that persisted in subsequent guides for the game and its expansions.
The 2009 reference book The Essential Atlas located Grizmallt in grid square L-9. In his Hyperspace article "The Written Word," published on March 5, 2010, author John Hazlett drew upon a reference to Grizmallt from the 2005 reference book The New Essential Chronology to allude to the evolution of language between Grizmallt and Naboo over time, while also creating a "fun" incident involving the character Jar Jar Binks.