The son of Negus Haile Melekot of Shewa, prince Sahle Maryam was born in Angolela, near Debir Brihan, Shewa. Upon the death of his father in 1855 he, just named as his successor as king of Shewa by his father, was taken prisoner by Emperor Tewodros II, a former minor noble originally named Kassa of Qwara, who had usurped the Imperial throne from the last Emperor of the elder Gondar branch of the Solomonic dynasty (either Emperor Yohannes III or Emperor Sahle Dengel; the historical record is uncertain here). Following Tewdoros' conquest of Shewa, young Sahle Maryam of Shewa was imprisoned on the Emperor's mountain stronghold of Magdala, but was treated well by the Emperor, even marrying Tewodros's daughter Alitash.
Upon Sahle Maryam's imprisonment, his uncle, Haile Mikael had been made ruler of Shewa by Emperor Tewodros II with the title of Meridazmach. However, Meridazmach Haile Mikael rebelled against Tewodros, resulting in his being replaced by the non-royal Ato Bezabeh as governor of Shewa. However, Ato Bezabeh promptly rebelled against the Emperor and proclaimed himself King of Shewa. Although the Shewan royals imprisoned at Magdala had been largely complacent as long as a member of their family ruled over Shewa, this usurpation by a commoner was not palatable to them. They plotted the escape of Sahle Maryam from Magdala; with the help of Queen Worqitu of Wollo, he escaped from Magdala the night of 1 July 1865, abandoning his wife, and returned to Shewa. Enraged, Emperor Tewodros slaughtered 29 Oromo hostages then had 12 Amhara notables beaten to death with bamboo rods.
Bezabeh's attempt to raise an army against Sahle Maryam failed miserably; thousands of Shewans rallied to the flag of the son of Haile Melekot and even Bezabeh's own soldiers deserted him for the returning prince. Sahle Maryam entered Ankober and proclaimed himself Negus with the name of Menelik. While Menelik reclaimed his ancestral crown, he also made a claim on the Imperial throne, as a direct descendant male line of Emperor Lebna Dengel. However, he made no overt attempt to assert this claim during this time; Marcus interprets his lack of decisive action not only to Menelik's lack of confidence and experience, but that "he was emotionally incapable of helping to destroy the man who had treated him as a son. By failing to take part in the 1868 Expedition to Abyssinia, he allowed his rival Kassa to benefit with gifts of modern weapons and supplies from the British. Afterwards other challenges -- a revolt amongst the Wollo to the north, the intrigues of his next wife Baffana to replace him with her choice of ruler, military failures against the Arsi Oromo to the south east -- kept Menelik from directly confronting Kassa until after his rival had brought an Abuna from Egypt who crowned him Emperor Yohannes IV. Eventually Menelik acquiesced to Yohannes superior position, and on 20 March 1878 "approached Yohannes on foot, carrying a rock on his neck, his face down in the traditional form of submission. However, very aware of how precarious his own position was, Yohannes recognized Menelik as Negus of Shewa and gave him numerous presents which included four cannons, several hundred modern Remington rifles, and ammunition for both.
In 1883, Negus Menelik married Taytu Betul, a noblewoman of Imperial blood, and a member of one of the leading families of the regions of Semien, Yejju in modern Wollo, and Begemder. Her paternal uncle Dejazmatch Wube Haile Maryam of Semien had been the ruler of Tigray and much of northern Ethiopia. She had been married four times previously and exercised considerable influence. Menelik and Taytu would have no children. Menelik had, previous to this marriage, sired not only Zauditu (eventually Empress of Ethiopia), but also another daughter, Shoaregga (who married Ras Mikael of Wollo), and a son, Prince Wossen Seged, who died in childhood. In 1886 Menelik married Zauditu to Emperor Yohannes’s son, Ras Araya Selassie. Ras Araya Selassie died in May 1888 without any issue by her, and the Emperor Yohannes was killed in a war against the dervishes at the Battle of Gallabat (Matemma) on May 10, 1889.
The succession now lay between the late emperor’s natural son, Ras Mengesha, and Menelik of Shewa, but the latter was able to obtain the allegiance of a large majority of the nobility on November 4. Menelek was consecrated and crowned as Emperor Menelik II of Ethiopia shortly afterwards. Menelek argued that while the family of Yohannes IV claimed descent from King Solomon and the Queen of Sheba through females of the dynasty, his own claim was based on uninterrupted direct male lineage which made the claims of the House of Shewa equal to those of the elder Gondar line of the dynasty.
Menelik, and later his daughter Zauditu, would be the last Ethiopian monarchs who could claim uninterrupted direct male descent from King Solomon and the Queen of Sheba (both Lij Iyasu and Emperor Haile Selassie were in the female line, Iyasu through his mother Shewarega Menelik, and Haile Selassie through his paternal grandmother, Tenagnework Sahle Selassie).
In 1889, while claiming the throne against Mengesha, Menelik signed at Wuchale in Wollo province (Uccialli in Italian) a treaty with Italy, acknowledging the establishment of the new Italian Colony of Eritrea with its seat at Asmara. This colony had previously been part of the northern Tigrayan territories from which Ras Mangasha and his allies such as Ras Alula generated support, and the establishment of the Italian colony weakened the northern Rases. Menelik had stated that Eritrea (Lands North of Merab Melash) did not belong to his Abyssinian(Ethiopian Empire) kingdom:
However, it was soon found that the Italian version of one of the articles of the treaty placed the Ethiopian Empire under an Italian protectorate, while the Amharic version did not. Emperor Menelik denounced it and demanded that the Italian version be changed. Negotiations failed, so Menelik renounced the treaty, leading Italy to declare war and invade from Eritrea. After defeating the Italians at Amba Alagi and Mekele, Menelik inflicted an even greater defeat on them, at Adowa on March 1, 1896, forcing them to capitulate. A treaty was signed at Addis Ababa recognizing the absolute sovereign independence of Ethiopia.
Menelik II's French sympathies were shown in a reported official offer of treasure towards payment of the indemnity at the close of the Franco-Prussian War, and in February 1897 he concluded a commercial treaty with France on very favourable terms. He also gave assistance to French officers who sought to reach the upper Nile from Ethiopia, there to join forces with the Marchand Mission; and Ethiopian armies were sent towards the Nile, but withdrew when the Fashoda Crisis between France and the United Kingdom cooled off. A British mission under Sir Rennell Rodd in May 1897, however, was cordially received, and Menelik agreed to a settlement of the Somali boundaries, to keep open to British commerce the caravan route between Zaila and Harrar, and to prevent the transit of munitions of war to the Mahdists, whom he proclaimed enemies of Ethiopia.
In the following year the Sudan was reconquered by an Anglo-Egyptian army and thereafter cordial relations between Menelik and the British authorities were established. In 1889 and subsequent years, Menelik sent forces to co-operate with the British troops engaged against a Somali leader, Sayyid Mohammed Abdullah Hassan.
Menelik had in 1898 crushed a rebellion by Ras Mangasha (who died in 1906). He directed his efforts thenceforth to the consolidation of his authority, and in a certain degree, to the opening up of his country to western civilization. Menelik’s clemency to Ras Mangasha, whom he compelled to submit and then made hereditary Prince of his native Tigray, was ill repaid by a long series of revolts by that prince. Menelek focused much of his energy on development and modernization of his country after this threat to his throne was firmly ended. He had granted in 1894 a concession for the building of a railway to his capital from the French port of Djibouti, but, alarmed by a claim made by France in 1902 to the control of the line in Ethiopian territory, he stopped for four years the extension of the railway beyond Dire Dawa. When in 1906 France, the United Kingdom and Italy came to an agreement on the subject, granting control to a joint venture corporation, Menelek officially reiterated his full sovereign rights over the whole of his empire.
In May 1909 the emperor’s grandson Lij Iyasu (later Iyasu V) by his late daughter Shoaregga, then a lad of thirteen, was married to Romanework Mengesha, granddaughter of the Emperor Yohannes IV by his natural son Ras Mengesha, and was also the niece of Empress Taytu. Two days later Iyasu was publicly proclaimed at Addis Ababa as Menelik’s successor. At that time the emperor was seriously ill and as his ill-health continued, a council of regency — from which the empress was excluded — was formed in March 1910. Lij Iyasu's marriage to Romanework Mengesha was dissolved, and he married Seble Wongel Hailu, daughter of Ras Hailu, and granddaughter of Negus Tekle Haymanot of Gojjam. On December 12, 1913 Emperor Menelek II died of a stroke and was buried secretly at the Se'el Bet Kidane Meheret Church on the grounds of the Imperial Palace. Official news of his death was kept from the public for several years by order of Lij Iyasu, although it was soon widely known. Following the deposition of Lij Iyasu in 1916, and the crowning of Menelik's daughter Zauditu as Empress of Ethiopia, Menelik II was reburied in the specially built church at Ba'eta Le Mariam Monastery of Addis Ababa.
Menelik II was fascinated by modernity, and like Tewodros II before him, had a keen ambition to introduce Western technological and administrative advances into Ethiopia. Following the rush by the major powers to establish diplomatic relations following the Ethiopian victory at Adowa, more and more westerners began to travel to Ethiopia looking for trade, farming, hunting and mineral exploration concessions. Menelik II founded the first modern bank in Ethiopia, the Bank of Abyssinia, introduced the first modern postal system, signed the agreement and initiated work that established the Addis Ababa-Djibouti railway with the French, introduced electricity to Addis Ababa, as well as the telephone, telegraph, the motor car and modern plumbing. He attempted unsuccessfully to introduce coinage to replace the Maria Theresa thaler. During the 1890s, Menelik heard about the modern method of executing criminals using electric chairs, and he ordered 3 for his kingdom. When the chairs arrived, Menelik learnt they would not work, as Ethiopia did not yet have an electrical power industry. Rather than waste his investment, Menelik used one of the chairs as his throne, sending another to Lique Mequas Abate. During a particularly devastating famine caused by Rinderpest early in his reign, Menelik II personally went out with a hand-held hoe to furrow the fields to show that there was no shame in plowing fields by hand without oxen, something Ethiopian highlanders had been too proud to consider previously. He also forgave taxes during this particularly severe famine.
Later in his reign, he established the first Cabinet of Ministers to help in the administration of the Empire, appointing trusted and widely respected nobles and retainers to the first Ministries. These ministers would remain in place long after his death, serving in their posts through the brief reign of Lij Iyasu and into the reign of Empress Zauditu. They played a key role in deposing Lij Iyasu.