A close friend of Frodo Baggins, he accompanied the Hobbit to Rivendell in TA 3018, where he became one of the Companions of the Ring. He ventured with the Company as far as Parth Galen before becoming separated with Peregrin Took and captured by Orcs. As the Orc-band proceeded to take the Hobbits to Isengard, they were ambushed by the Rohirrim, allowing Merry and Pippin the chance to escape into Fangorn Forest. Here they befriended the Ent Fangorn (Treebeard) and helped persuade the Ents to attack Isengard. (Because Merry and Pippin both drank Ent-draughts while in Fangorn, they became the largest Hobbits in history, standing at least four and a half feet tall.)
Later, Merry joined the service of King Théoden of Rohan as his esquire. Ordered to remain in Rohan while the Rohirrim rode to Gondor, Merry rode with Éowyn to Gondor, where together they slew the Lord of the Nazgûl in the Battle of the Pelennor Fields. (Merry nearly died of the Black Breath, but was healed by Aragorn.)
Following the War of the Ring, Merry was rewarded for his valour by being made a knight of Rohan. Upon his return to the Shire, he became one of the leaders of the Hobbit forces in the Battle of Bywater. When his father died, he became Master of Buckland, and in FO 14 was made a Counsellor of the North-kingdom. He married Estella Bolger, sister of his friend Fredegar, and continued to maintain contact with the friends he had made during the war. He wrote a number of scholarly works, among them Herblore of the Shire, The Reckoning of Years, and Old Words and Names in the Shire.
In FO 64, he and Pippin resigned their offices and rode to Rohan and Gondor, dying in the latter realm. They were buried in the House of the Kings.
In Rohan he was known as Master Holbytla and Holdwine of the Shire.
To Men of Gondor, he was called Master Perian.
As Master of Buckland, he was also known as Meriadoc the Magnificent.
In genuine Hobbitish, Merry’s true name was Kalimac – generally abbreviated to Kali – which in genuine Westron meant ‘jolly’ or ‘gay.’