"Tell me about your professional background" could mean anything from what types of jobs you've had to the training or education you completed to get to this stage in your career. Professional background is one of those phrases that you can use to describe who you are, where you've been and what you'd like to accomplish. On the other hand, if you're in an interview and the recruiter or hiring manager specifically asks about your professional background and follows up with "Tell me about your work history," you'll know that she's inquiring about employment and not much else.
In many cases, "professional background" does refer to work history. Many job seekers use the subheading "Professional Experience" or "Professional Background" when they're describing their previous employment, and that's perfectly acceptable. But, for online application processes, the phrase "Work History" works better because many of the applicant tracking systems don't recognize the phrase "professional background." So, if you're handing a hard copy resume to an interviewer, refer to your professional background, but if you're completing an online application, change the section title to "Work History" on your resume before you upload it.
Position Rarely Matters
Whether you're a typist, shipping clerk or president of a company, one of the most sought-after qualifications is professionalism. Professionalism isn't a trait reserved just for white-collar workers, so don't think that if you work on a production line that you can't refer to your professional background. If you need to justify why you're calling your work history your professional background, it's because you exhibit the same type of pride in the work you do just as much as the CEO of the organization that employs you. The U.S. Department of Labor pointedly states what professionalism is and what it isn't on the department's page for its Office of Disability Employment Policy: professionalism means "conducting oneself with responsibility, integrity, accountability and excellence." That applies to every job, no matter the rank or pay.
Training and Education
Academic credentials are one thing, but your training and education are also part of your professional background. You might not refer to four years at university as your professional background, but you certainly should consider leadership training, job skills training and orientation as components of your professional background. These are the experiences that have a direct impact on your employment and performance. Naturally, there are exceptions, such as professional degrees in medicine and law, but even physicians and attorneys complete training outside the academic setting that prepare them for their careers.
How You Look on Paper
Your resume is a partial summary of your professional background, but it's by no means a full recitation of your professional experiences, training, education and exposure that makes up who you are. A resume is a marketing tool – it's what you use to get in front of a recruiter or hiring manager – it's just not a summary of your professional background because there are so many other factors that contribute to your professional growth and development.
Paying it Forward
In addition to what you've done to advance your career path and improve your own knowledge, your professional background might include what you've done to help others. Being a mentor, supervisor, teacher or simply a colleague willing to help someone else learn the ropes also is part of your professional background. Likewise, your participation in industry associations, such as sitting on a discussion panel so others can learn more about your field, is a component of your professional background.