Becoming a rabbi is not the same straightforward process as becoming a minister or a priest. Different sects of Judaism have different requirements. However, it can be said that most rabbis have earned a college degree, and have participated in post-graduate rabbinical studies through a seminary. In some sects, a person must also spend time in Israel prior to working for a congregation.
Studying to become a rabbi does not mean one gets to be one in the practical sense. Usually, a person may begin work with either a tiny congregation, or as the assistant in a large congregation. This is because each Jewish community makes its own decision about who to hire. There is not a huge organization like the papacy deciding where to send one when one has become a rabbi. Instead, a person has to apply for jobs, much like one would apply for any other job. The field can be competitive, so significant study and skill increases one’s chances of finding work.
The first requirement to become a rabbi is that one must be Jewish. If one is not Jewish, one must first convert to Judaism. It is fine for a person who was not born Jewish to convert, and many great rabbis were first part of some other religion. Conversion to Judaism is a lengthy and demanding process, requiring work and spiritual deliberation.
In some sects of Judaism, a woman cannot become a rabbi. A woman interested in this position should probably belong to either a Reform, Reconstuctionist, or Conservative Jewish sect. In general, neither Hasidic nor Orthodox Judaism will ordain female rabbis.
Prospective rabbis should be excellent scholars of Hebrew. This is because studies of the Torah are interpreted through the Talmud. One must be able to read Talmud and the Mishnah in its original form, as there is often disputation over the interpretation of words.
If one attends a yeshiva, a Jewish school, as a child, one learns Hebrew along with other studies. In fact yeshiva education often inspires a scholar to become a rabbi. However, if one has not had this advantage, taking Hebrew in college and really mastering the language is essential. If one has not mastered Hebrew in college, one can still train to be a rabbi, but this means further study in Hebrew prior to taking other studies at a rabbinical school.
A rabbi interprets Torah, and also leads the congregation, performs marriages, gives talks and offers counseling. Most rabbis, like most religious leaders, undergo both psychological testing and background checks prior to being allowed to work for a congregation. This helps weed out people who might take advantage of their position as spiritual leaders.
Officially one does not become a rabbi until the title is given to the person by other rabbis or through being hired by a congregation. Since the term encompasses ministry, a person in this position must be ministering or teaching.