Your background is your personal history. It includes where you were born, what kind of family you grew up in, where you went to school, and what jobs you've had.
The phrase "have a __ background" is often used in business to describe a person's work and education history. You can use different positive adjectives to describe a person's background:
He has a strong background in publishing.
We're looking for someone who has an extensive background in biology.
In both of these examples, "in ___" was used to tell the area or field of the person's background.