To become a city prosecutor, you must complete the legal education required for you to practice criminal law in your jurisdiction, obtain a law license and submit a job application. Prosecutor's offices hire entry-level and mid-level lawyers. Many are willing to hire new lawyers right out of school, so you rarely need work experience to be considered for a position. Your academic record, extracurricular activities and summer internships are often used as indicators of aptitude for the job, however.
Most countries have multiple court systems that correspond to jurisdictional grants of authority. Each court system has its own criminal prosecutor's office that employs the lawyers that prosecute cases for the government. The city prosecutor's office is typically the lowest, or most local, prosecutorial level. For example, the US has city, state and federal prosecutors, all of whom have their own offices attached to the court system controlling that jurisdiction.
To obtain any job as a lawyer, you typically need to complete the required legal education in your jurisdiction, take a licensing exam and maintain a license to practice law where the job is located. In the US, for example, to become a city prosecutor you need a Juris Doctorate (J.D.) degree from an accredited law school. A law degree enables you to sit for the bar exam in a state where you want to practice. Once you pass the exam, you are eligible to apply for a license to practice law in that US state.
During your final year at law school or any time after you graduate, you can apply for a job at a city prosecutor's office. You don't need to have passed the bar or attained your license to apply. These things can be pending during your first year of work, but your continuation in the position will be predicated on their successful completion. If you are transferring into a city prosecutor's office from another legal job as a mid-level hire, you should already have these credentials. Your selection for the job as a mid-level hire will depend largely on your prior legal experience.
To become a city prosecutor in an entry-level position right out of school, your academic record should show an aptitude for the type of legal work you will be performing. Attaining high grades in criminal law and procedure classes is advisable. School activities showing an ability to argue a case, such as participation on the moot court team, will also help your candidacy.
One of the best ways to show you have what it takes to become a city prosecutor is to use the two summers during your law school education to intern in a prosecutor's office. Recommendations from supervisors will often go a long way in enhancing your application. In lieu of this type of internship, make sure you exhibit the type of legal acuity, verbal ability and outgoing personality traits that will enable you to prosecute a case in open court.