Upon switching leagues in 1890, the franchise became the only one in MLB history to win pennants in different leagues in consecutive years. Manager Wilbert Robinson, popularly known as "Uncle Robbie", restored the Brooklyn team to respectability, winning pennants in 1916 and 1920 and contending perennially for several seasons. Upon assuming the title of president, however, Robinson's ability to focus on the field declined, and the teams of the late 1920s became known as the "Daffiness Boys" for their distracted, error-ridden style of play. After his removal as club president, Robinson returned to managing and the club's performance rebounded somewhat.

It was during this era that Willard Mullin, perhaps the finest cartoonist the sporting press has ever known, fixed the Dodgers forever with the loveable nickname of "Dem Bums" - when, after hearing his cab driver ask "So how did those bums do today?" Mullin decided to sketch an exaggerated version of famed circus clown Emmett R. Kelly, Jr. to represent the Dodgers in his much-praised cartoons in the New York World-Telegram. Both the image and the nickname caught on, so much so that many a Dodger yearbook cover featured a Willard Mullin illustration with the Brooklyn Bum.

Perhaps the highlight game of the Daffiness Boys era came, interestingly enough, well after Wilbert Robinson had left the dugout. Managed now by Casey Stengel (who played for the Dodgers in the 1910s), the 1934 Dodgers rankled when New York Giants manager Bill Terry - asked about the coming pennant race at the previous winter's baseball meetings - cracked infamously, "Is Brooklyn still in the league?" At season's end, the Giants were tied with the St. Louis Cardinals for the pennant with the Giants needing to beat the Dodgers two games to stay alive. Stengel led the Dodgers to the Polo Grounds for the showdown and beat the Giants twice to knock them out of the pennant as the soon-to-be-nicknamed "Gas House Gang" nailed the pennant cold by beating the Cincinnati Reds the same two days. Batting helmets were introduced to Major League Baseball by the Dodgers in 1941

The only Brooklyn World Series title came in 1955. Rebuilt into a contending club first by Larry MacPhail and then the legendary Branch Rickey, the Dodgers won pennants in 1941, 1947, 1949, 1952, and 1953. In all five of those World Series, however, they proved unable to overcome the New York Yankees. Then, in 1955, the long-cried slogan "Wait 'till next year" became "This year is next year!" The fabled "Boys of Summer" Dodgers - despite their actual peak years having just passed - shot down the Bronx Bombers in seven games, led by the first class pitching of young lefthander Johnny Podres, whose key pitch was a changeup known as "pulling down the lampshade" because of the arm motion used right when the ball was released. Podres won two Series games including the deciding seventh, which turned on a spectacular double play that began with left fielder Sandy Amoros running down Yogi Berra's long fly, then throwing perfectly to shortstop Pee Wee Reese, who doubled up a surprised Gil McDougald at first base to preserve the Dodger lead.

The myth: cold-hearted Walter O'Malley just up and yanked Dem Bums off for California gold.

The fact: Walter O'Malley was nobody's saint, but neither was he just off on a gold rush. He sought as early as 1952 to buy new land in Brooklyn to build a more accessible and better arrayed ballpark than Ebbets Field. Beloved as it was, Ebbets Field had grown old before her time, to the point where the most pennant-competitive team in the National League couldn't sell the park out even in the heat of a pennant race. New York building czar Robert Moses, however, sought to all but jam a site in Flushing Meadows, Queens, down O'Malley's throat - a site featuring a city-built, city-owned park, Moses making it plain enough that he had no intention of allowing any privately-built, privately owned baseball stadiums in his New York. Only when he realized he wasn't going to be allowed to buy any fresh land in Brooklyn did Walter O'Malley begin thinking elsewhere.

For their part, Los Angeles itself wasn't even thinking of the Dodgers when city fathers attended the 1955 World Series looking to entice a team to move to the City of Angels - their original target had been the Washington Senators! But when he realized he'd need a contingency in case, at long last, Moses and New York's notoriously gamesmanship-addicted politicians refused to let him build a new Dodger home in Brooklyn, O'Malley sent word to the Los Angeles officials at the Series that he was interested in talking. Los Angeles offered him what New York refused him: a chance to buy land suitable for building a new ballpark. That the Dodgers left Brooklyn heartbroken is undisputable; that Walter O'Malley did it deliberately is not.

--Wikipedia