A Muslim is permitted to work in an organization which conducts both halal and haram activities as long as the person does not forget his or her religious duties. A Muslim who works in such places should consider that he is an ambassador of Islam, and hence he should represent his religion in the best way.
Dr. Sano Koutoub Moustapha, professor of fiqh and its principles, International Islamic University, Malaysia, states the following: There is no prohibition to work in an international organization which handles or conducts halal and haram activities as long as the person does not forget his or her obligations and duties. In other words, you are strongly recommended to work in such organizations with the hope to change and introduce the noble teachings of Islam through your good interaction and performance.
The Prophet (peace and blessings be upon him) commended the believer who mixes and interacts with the people, and he said that such a believer is better and closer to Allah than the believer who doesn’t mix or interact with people.
In addition, without mixing and interacting or working in such organizations, the message of Islam would not reach non-Muslims.
Therefore, I strongly recommend every Muslim to work and bear in mind that you are the ambassador of Islam through your behavior, attitude, and conduct. Islam expanded in many places in the world through the good conduct and behavior shown by its followers when they lived with non-Muslims. All in all, do your best for Islam and be always a positive agent of change in your works.