This post is part of a series in which Mark Armour and I count down the 25 best GMs in history, crossposting from our blog. For an explanation, please see this post.

[This one is from Mark]

Had Branch Rickey retired from baseball in 1942, before he ran the Dodgers, before he signed Jackie Robinson, his record as a general manager would still be enough to warrant consideration as the greatest GM in the game’s history. By that time he had already built one of history’s best organizations, winning six pennants and four World Series while completely revising baseball player development and instruction and inventing the farm system model that is still in place nine decades later. When you add in his Brooklyn years, both the building of one of baseball’s best and most iconic teams and his historic and courageous act to integrate the game, it is a relatively easy call. Summarizing Branch Rickey as a general manager is like summarizing Isaac Newton as scientist. Where do you begin?

By the age of thirty, Rickey had retired from his brief playing career and had received a law degree from the University of Michigan. The practice of law did not take, and by 1913 he was back in baseball, where he remained for the next five decades. He managed the Browns for two years, then was “kicked upstairs” when a new ownership group came on, becoming something like a general manager in 1916. A year later he moved cross-town, becoming president of the Cardinals and de facto GM, though the position did not yet formally exist. In 1919 he appointed himself the field manager and filled both jobs for six years.

Most of history’s best GMs have been blessed with excellent ownership that has provided the necessary resources with limited interference. Sam Breadon took control of the Cardinals in 1920, and proved to be the best thing that ever happened to Rickey. After a few years of non-contention, in 1925 Breadon relieved Rickey of his uniform and told him to concentrate on the front office part of his job, player development and scouting. Rickey was not happy, but history proved it to be a brilliant decision.

Branch Rickey first envisioned an organized “farm system” as a solution to the high cost of buying minor league players. A team could instead sign amateur players (for much less money) and then assume the cost of developing the players on teams under its control. At first Rickey’s efforts were (at least) bending the rules, which limited the number of players a major league team could control in the minors. Rickey instead had handshake agreements with many minor league teams that occasionally got the baseball commissioner to take notice. In the early 1930s, after continual lobbying from Breadon and Yankee owner Jacob Ruppert, baseball significantly relaxed their rules on teams’ owning or controlling farm teams, and the Cardinals and Yankees soon had huge farm systems. And, not coincidentally, the two best teams in baseball.

Soon after Rickey created his system, he realized that he needed a cohesive philosophy of scouting, instruction, and coaching. The Cardinals were not signing ready-made players; they were signing boys who needed to be taught how to play. Every part of the game—bunting, sliding, run-down plays, and so on—Rickey wanted to be taught consistently throughout the organization. And Rickey wanted the scouting and player-development parts of the system to work hand in hand. As Kevin Kerrane wrote in his classic book on scouting, “Rickey applied scouting insights to teaching, and vice versa.” Rickey became a legendary talent evaluator, able to make decisions quickly on players. Among other things, he valued speed and youth. No sentimentalist, he tried to trade players before they started to decline rather than after. With his huge farm system, he believed he could fill the holes created when he traded his veterans away.

From 1926 to 1946 the Cardinals won nine pennants and six World Series. Rickey did not have complete control of the club — Breadon hired and fired the managers, for example — and the relationship between the two men had become a bit strained by the early 1940s. When the Dodgers offered an ownership stake and more authority in October 1942, Rickey moved to Brooklyn.

The Dodger team Rickey inherited had just won 104 games. But make no mistake, this was not Rickey’s sort of team. Previous executive Larry MacPhail ran his clubs like a man in a hurry, like he needed to win today because he might not be around tomorrow. As good as the 1942 Dodgers were, only a few good players—notably Pee Wee Reese and Pete Reiser—were in their twenties. But MacPhail had overseen such a dramatic improvement in the Dodgers’ financial position that Rickey had the resources to build the organization that he wanted. He wasted no time getting to work.

Rickey could not do much with the war going on — all his players were in the service — but he worked on building his farm system to be ready. In 1943 alone the Dodgers signed Rex Barney, Duke Snider, Gil Hodges, and Ralph Branca. Over the next couple of years Brooklyn added Carl Erskine and Clem Labine, two other mainstays of Dodger teams to come.

The most important event of Rickey’s career, of course, was the signing of Jackie Robinson in October 1945, the first step on the road to ending the Major Leagues’ decades-long prohibition on dark-skinned players. Rickey has been justifiably praised for this courageous and ethical act and his related decisions to sign other black players in the coming years. But more than that, Rickey dramatically improved his team, and in a short time had dramatically improved the quality of play in the major leagues. When Robinson was signed it effectively opened up a huge new source of talent, the biggest new pool in history. As baseball soon discovered, there were dozens of good players, some of them among the greatest players ever, ready to sign cheaply with the first team that asked them. By the end of the 1940s eleven black players had made their debuts in the Major Leagues, eight of whom ended up playing at least five full Major League seasons. Among them were three Dodgers—Jackie Robinson, Roy Campanella, and Don Newcombe—whose extraordinary play helped define an era and one of history’s most beloved teams.

The integration of the Dodgers went relatively smoothly, thanks both to the tremendous care taken by Rickey and his staff, and the ability and character of these three players. Rickey traded away several southern players during and after the 1947 season, but most of these deals were classic Rickey moves that helped the ball club. In December he dealt Dixie Walker, one of the team’s best and most popular players, to the Pirates, a deal many have interpreted as an indication that Rickey wanted Walker off the team. In fact, it was a great baseball trade: Rickey acquired infielder Billy Cox and pitcher Preacher Roe, who played huge roles on the coming teams. Eddie Stanky was dealt the following March, allowing Robinson to move to second base and Gil Hodges to play first, another very solid baseball move.

After losing a pennant playoff in 1946, the Dodgers won NL pennants in 1947 and 1949 and then lost in 1950 on the season’s final weekend. Unlike the prewar teams, by 1950 the Dodgers had several good players in their twenties and more on the way. In late 1950 Rickey began to sense that his position had weakened with his partners and decided to cash in his stake and take a job running the Pittsburgh Pirates. Walter O’Malley bought Rickey’s share and gained control of the club. The core of talent Rickey left behind won four more pennants and the 1955 World Series. The acolytes he left, including Buzzie Bavasi and Al Campanis, built on Rickey’s foundation to create and maintain baseball’s model organization for another four decades.

Rickey was 69 years old and taking over a team that needed a slow, patient overhaul. The Pirates signed a few bonus babies that did not bear fruit, but he slowly began to improve the organization one player at a time. When owner John Galbreath finally let Rickey go, after five years, the team’s assets included youngsters Roberto Clemente, Bill Mazeroski, Dick Groat, Bob Friend and Vernon Law. It would take another five years for the Pirates to win a pennant, but Rickey certainly did his part.

Rickey never really stopped working. He played a leading role in trying to form the Continental League, a third major league that did not quite get off the ground. In 1962 the 81-year-old took a job as a senior adviser to Cardinal owner Gussie Busch, which proved awkward for GM Bing Devine and everyone else. Rickey left after the 1964 championship.

He died a year later, leaving behind an unmatched resume in the game. As a general manager he dramatically changed how teams find and develop players, and what players are allowed to play the game. His place as the greatest GM in baseball history is secure.

To read more about the history of baseball operations and the GM, please buy our new book In Pursuit of Pennants–Baseball Operations from Deadball to Moneyball via the publisher or at your favorite on-line store.