Born Louis Honoré Charles Antoine Grimaldi in Baden-Baden, Germany, he was the son of Prince Albert I of Monaco (1848 - 1922), and Lady Mary Victoria Douglas Hamilton[?] (December 11, 1850 - May 14, 1922), of Lanarkshire, Scotland, she being the daughter of William Alexander Anthony Archibald (Hamilton), 11th Duke of Hamilton[?], and his wife Princess Marie Amelie Elizabeth Caroline of Baden.
Within a year of his parents' marriage Louis was born, but the strong-willed 19-year-old Scots girl disliked Monaco and everything about it. Shortly thereafter, she left the family permanently and the princely couple's marriage was annulled in 1880. Louis was raised in Germany by his mother and stepfather, Tassilo, prince Festetics von Tolna, along with his half-sister, Alexandra, and did not see his father until age 11 when he was obliged to return to Monaco to be trained for his future royal duties.
Louis' father, Prince Albert I, was a dominating personality who had made Monaco a center of cultural activity and whose intellectual achievements were recognized around the world. Unhappy, living with his cold and distant father, as soon as he was old enough, Louis went to France, enrolling in the Saint-Cyr Military Academy[?]. Four years later, after graduating, he asked to be posted with the French Foreign Legion fighting the wars in the African colonies.
While stationed in Algeria, he met Marie Juliette Louvet (1867 - 1930), the cabaret-singer daughter of the French laundrywoman who worked for the prince's regiment. Reportedly, Prince Louis fell deeply in love but, because of what in those days was seen as her ignominious station in life, his father would not permit the marriage. It has been asserted that Louis ignored his father and married Juliette in 1897: there is, however, no evidence for this allegation. Their daughter Charlotte Louise Juliette, born on September 30, 1898 in Constantine, Algeria[?], was declared illegitimate.
For ten years, Louis served in the military with distinction, being awarded the cross of the Legion of Honor. In 1908 he returned home, leaving behind his mistress and daughter. At the outbreak of World War I, he re-enlisted in the French army, proving to be one of the Fifth Army’s most outstanding soldiers. He was made a Grand Officer of the Legion of Honor and eventually became a Brigadier General. While many of his Grimaldi ancestors had served in the military, none had acquitted themselves with more distinction than Louis.
A political crisis loomed for the Prince because without any other heir, the throne of Monaco would pass to his first cousin, the duke of Urach[?], a German nobleman who was a son of Prince Albert's aunt, Princess Florestine of Monaco. To ensure this did not happen, in 1911 a law was passed recognizing his bastard daughter, Charlotte, as Louis's acknowledged heir, and making her part of the sovereign family. This law was later held to be invalid under the 1882 statutes. Thus another law was passed in 1918 modifying the statutes to allow the adoption of an heir, with succession rights. Charlotte was formally adopted by Louis in 1919, and became Charlotte Louise Juliette Grimaldi, Hereditary Princess of Monaco, and Duchess of Valentinois[?].
On June 27, 1922, Prince Albert I died in Paris. Louis Grimaldi ascended to the throne as Louis II, Prince of Monaco. While his reign could never achieve the grandeur of his father, Louis II left an indelible imprint on the tiny principality. In 1924 the Monaco Football Club was formed and in 1929, the first Grand Prix of Monaco automobile race was held, won by Charles Grover (aka "Williams") driving a Bugatti painted in what would become the famous British racing green color.
In 1931, the prestige of Monaco's cultural life received a boost when René Blum[?] was hired to form the "Ballet de l’Opera a Monte Carlo." Just before the outbreak of World War II in 1939, a modern large football stadium had been built where the World University Games[?] were staged at the newly named "Stade Prince Louis II."
While Prince Louis' sympathies were strongly pro-French, he tried to keep Monaco neutral during World War II but supported the Vichy France government of his old army colleague, Marshall Petain. Nonetheless, his tiny principality was tormented by domestic conflict partly as a result of Louis' indecisiveness and also because the majority of the population was of Italian descent and they supported the fascist regime of Italy's Benito Mussolini. In 1943, the Italian army invaded and occupied Monaco, setting up a fascist government administration. Shortly thereafter, following Mussolini's collapse in Italy, the German army occupied Monaco and began the deportation of the Jewish population. Among them was René Blum, founder of the Opera, who died in a Nazi concentration camp. Under Prince Louis' secret orders, the Monaco police, often at great risk to themselves, warned people in advance that the Gestapo was about to arrest them.
However, throughout the War, Prince Louis' vacillation caused an enormous rift with his grandson Rainier, the heir to the throne, who strongly supported the Allies against the Nazis. Following the liberation of Monaco by the Allied forces, the 75-year-old Prince Louis did little for his principality and it began to fall into severe neglect. By 1946 he was spending most of his time in Paris and on July 27th of that year married Ghislaine Marie Françoise Dommanget[?] (1900 - 1991), a French film actress and former wife of actor André Brulé. Absent from Monaco during most of the final years of his reign, he and his wife lived at Marchais, the family estate near Paris.
Princess Charlotte ceded her succession rights to her son Rainier in 1944, when he became Hereditary Prince. Thus, Louis was succeeded by Charlotte's son, Prince Rainier III.
There is no mention of Juliette Louvet in the authorized biography of her grandson, Prince Rainier III, who is Monegasque by nationality but genealogically is Algerian, French, Italian, and Scottish. Louis' second wife, Princess Ghislaine, lived for another 42 years after his death; she died on April 30, 1991 in Paris, where she was interred in the Passy Cemetery.