Ordained Ministry in the Presbyterian Church has evolved as an important part of the historic Christian tradition known as the Reformed Christian tradition, which traces to the founding religious ideas of John Calvin (1509-1564). While all members of the Presbyterian Church are called to be ministers in a general sense, there is a tradition of three types of "ordered ministries". These three offices include Ordained Pastoral Ministry (sometimes called a "teaching elder" who is trained in Theology and Scripture), or a "ruling Elder" (who may do some teaching, and also administer recognized sacraments), or thirdly, ordination as a deacon. Ministers and elders are both referred to in this tradition as "presbyters" (from the Greek term for church leaders) from which this Christian tradition derives its name, the Presbyterian Church. Both ordained ministers and ordained elders are entitled to preach and have sacramental function in the church. Deacons, on the other hand, are ordained for administrative, financial, and managerial work within the church.
There is more than one church organization that goes by the name "Presbyterian", but the largest Presbyterian Church organizations have strict rules for the training and ordination for ministry. The two largest Presbyterian churches in the USA are the Presbyterian Church in American (PCA) and the larger Presbyterian Church, USA (PCUSA). For all those who seek to become ordained as a Presbyterian minister, the most common process begins with successfully completing graduate study at an ATS-accredited Theological seminary (ATS=Association of Theological Schools) and then fulfill the further requirements for formal ordination in the Church. These steps normally include extensive interviews and an examination process. Simply graduating from seminary is not the same thing as ordination - ordination to ministry in the Presbyterian Church is an act of the Church itself, which the church oversees by granting credentials to the individual as a legally ordained minister in the Presbyterian Church.
It is, however, possible to become ordained as a Presbyterian Minister (in the smaller Cumberland Presbyterian Church, for example) in exceptional circumstances without a formal seminary degree, but this is not encouraged by most Presbyterian church organizations which historically emphasize a professional and theological training that is considered necessary for the kind of responsible and mature leader that a church congregation can depend upon. Even in these circumstances, formal examinations are still a part of the ordination process, and further education is likely to be strongly encouraged and the ordination process may depend on the successful completion of continued study.
Becoming ordained as a Presbyterian minister is similar to Christian ministry in any church. Christian ministry is rarely lucrative, often stressful, and typically involves a person's entire family because pastors and elders are "on call" virtually 24 hours every day in times of family crisis, similar to a medical doctor. Becoming ordained as a Presbyterian minister is no exception to this. However, for those members of the Presbyterian Church with a profoundly personal experience of being called by God to the work of the Church, and whose call is recognized and acknowledged by the church, seeking to become ordained can be a life-changing step toward a career and vocation that is deeply fulfilling, profoundly meaningful, and rewarding in ways that are not to be measured in mere financial gain.