Finally he followed his heart, which took him south to Philadelphia, where the Dodgers were playing the Phillies. Berg singled in a run in his first major league game, to the delight of a clump of recent Princeton graduates in the stands.
After this snappy debut Berg's first summer of professional baseball was more of an ordeal. Over 49 games he hit .186. Then he was off to Paris. His French was so impressive that his tuition at the Sorbonne was waived. The Dodgers didn't sign Berg for 1924, and it wasn't until after he hit .311 for the International League's Reading Keys in '25 that he returned to the majors. In November, Chicago White Sox owner Charles Comiskey bought him from Reading for $50,000 to play shortstop. What Comiskey got was a law student.
Berg had decided to use his baseball earnings to pursue his law degree in the off-season. When he asked for permission to report to the White Sox after spring training in 1926, in order to finish the semester, Comiskey agreed. By May, when Berg reported, rookie Bill Hunnefield had won the shortstop job. The White Sox finished fifth, and Berg hit only .221 in the 41 games he played.
Over the following winter Comiskey's patience with Berg's studies dwindled. "My dear young man," the Old Roman wrote to Berg when Berg proposed skipping spring training again, "The time has come when you must decide as to the profession you intend following." Berg appealed to a dean at Columbia Law and was granted a leave of absence for the rest of the academic year.
Behind Hunnefield, he played in only 35 games in 1927, hitting .246. Mike Gonzales, an opposing scout, watched Berg play and filed the terse, damning dispatch that would become Berg's signature: "Good field. No hit." The unofficial word was that Berg could speak a dozen languages and couldn't hit in any of them.
One afternoon late in the season, a batter's swing connected with the hand of Sox catcher-manager Ray Schalk, breaking it. Then a foul tip split one of backup catcher Buck Crouse's fingers. Shortly after that, third-string catcher Harry McCurdy fractured his finger. From the bench Schalk bellowed, "Get me another catcher. Class C, Class D, I don't care, get me a catcher!"
"What do you mean, Class C, Class D?" came a low, even voice. "You've got a big league catcher sitting right here." It was Berg speaking. He was referring to first baseman Earl Sheely, who had caught in the minors. Schalk, however, thought Berg was talking about himself and sent him into the game. Berg had never caught before, but he performed flawlessly. "Now, I'll tell ya, Moe Berg was as smart a ballplayer as ever come along," said Casey Stengel. "Guy never caught in his life and then goes behind the plate like Mickey Cochrane."
Berg caught in nine more games that year and in 73 games in 1928. In 1929, after he graduated from Columbia Law, Berg became the White Sox's starting backstop. "Being allowed to catch is the best break I've ever had," Berg said.
That May he learned that he had survived New York State's brutal bar exam. He dined out alone the night the results were published, ordered a bottle of wine and drank a toast to his parents. The Manhattan law firm of Satterlee & Canfield hired him to do international contract litigation during the off-season. When journalists asked him about it, he said, "I don't want to be known as a ballplayer who read a book, and I don't want to be known as a lawyer with a bat on my shoulder. I practice law in the winter and I play ball in the summer, and I am careful to keep the two separate in my life."
In the spring of 1930 he tore ligaments in his knee when he caught his spikes in the dirt. Berg became so slow that, in Stengel's estimation, "a turtle could beat him to first base."