Spurred by war-induced prosperity, continental expansion, and television revenue, baseball led the transformation of professional sport from a commercial business to an entertainment industry. Moreover, baseball, like all organized sport, felt the impact of the social and cultural changes that swept over America. After World War Two umpiring truly became a profession, and by the end of the 1980s major league umpires were not only far better trained and organized than ever before but also a forceful and independent voice in baseball affairs.

Umpiring, like baseball itself, was enormously popular in the days following World War Two. By 1949 some fifty-nine minor leagues provided extensive on-the-job training for an unprecedented number of aspiring arbiters, but it was the umpire training school that was responsible for postwar umpires being so much better prepared than their predecessors. George Barr of the National League opened the first umpire training school in 1935, and in 1939 Bill McGowan of the American League established a second school. In 1946 Bill McKinley, who attended both the Barr and McGowan schools, became the first graduate of a training school to reach the major leagues. By the mid-1950s training school graduates were common, and by the 1960s it was virtually impossible to become a professional umpire without attending one of several training schools.

The umpire schools had profound effects on umpiring. First, graduates of the training schools were more knowledgeable of rules and more skilled in techniques than the earlier "self-taught" umpires. Second, formal training had the predictable effect of imposing uniformity of style and personality, as students were instructed "by the book" and maverick characters were weeded out. Finally--and most significantly--the umpire school was the catalyst that transformed umpiring from vocation to profession.

The professionalization of umpiring had profound effects. Formalized instruction and systematic career development attracted more middle-class college men, as umpiring was increasingly viewed less as a way of staying in professional sport than as a desirable career choice. And, reflecting the demographic shifts that prompted continental expansion, most umpires, like players, now hailed from the Sun Belt or the Pacific Coast. The lone area in which umpires lagged far behind players in mirroring the social changes of society at large was race. It was not until 1966, twenty years after Jackie Robinson broke the color line, that Emmett Ashford joined the American League and became the first black major league umpire. (He was also the first black professional umpire, breaking in with the Southwestern International League in 1951.) In 1973 Art Williams integrated the National League. Despite the strong presence of Latino players since the 1940s, Armando Rodriguez (1974) and Rich Garcia (1975), both in the American League, were the first Hispanic umpires in the majors.

Umpires also adopted a more professional attitude. They candidly admitted errors and portrayed themselves not as omnipotent enforcers of the law who demanded respect but as impartial judges who deserved respect. That umpires were skilled but fallible men became clearly visible in 1956, when Ed Rommel and Frank Umont broke a long-standing taboo by wearing eyeglasses on the field. But the most important effect of growing professionalization was that umpires increasingly viewed themselves as deserving the pay and perquisites of professionals.

In contrast with the strong support from league headquarters for their actions on the field, umpires historically were unable to protect themselves from monetary and personnel injustices because they negotiated individually instead of collectively with the leagues. Umpires repeatedly were dismissed arbitrarily, and in 1953, for the first time in fifteen years, umpires received a modest salary increase--a salary range of $6,000 to $16,000 and an increase in World Series pay to $3,000. Early efforts at organizing were to no avail, and in 1945 Ernie Stewart of the American League was fired for alleged unionizing activity. But in 1963, led by Augie Donatelli, umpires in the Senior Circuit organized the National League Umpires Association, headed by Chicago labor attorney John J. Reynolds. After Reynolds's success in raising salaries, American League umpires became unionists. When Bill Valentine and Al Salerno were dismissed in 1968, allegedly for incompetence but patently for unionizing activities, an appeal to the National Labor Relations Board resulted in umpires in both leagues being organized into the Major League Umpires Association. A one-day strike of the first game of the championship playoffs on October 3, 1970, the first by umpires in major league history, prompted the league presidents to recognize the Association and negotiate a labor contract that set a minimum salary of $11,000 and raised the average salary to $21,000.