If you study part-time, you have automatically less energy to invest in your current job. But: If you are smart about it, your career will already develop during your part-time master studies. The reason is simple: You will learn a lot of practical knowledge. You will expand your competencies on a weekly basis. While your colleagues stay at the same level of knowledge, you will be in the fast lane. Where others might take longer to find ideas and solutions, you can find academically sound shortcuts in a truly short time with fresh knowledge from a top business school. This way, during your part-time graduate studies, you can put yourself in a good position internally for the time after graduation. This only works if the contents of your chosen Master's programme are in demand at your workplace. However, if you need your new qualifications to change jobs or industries, you will certainly find a healthy way to reconcile your current job and your studies.
Some HR departments are particularly interested in applicants who have completed a part-time Master's degree. Compared to the combination of a Bachelor's and Master's degree in one go, you simply have two and a half years more career experience, and you have proven that you are resilient and disciplined.