A "diligent worker" is someone who puts in a lot of effort and is hardworking in their job or tasks, consistently showing dedication and perseverance to get things done well. Full definition
It's common for diligent workers to continually absorb more of the business's workload, and if this process goes on too long it can easily lead to burnout. (smallbusinessesdoitbetter.com)
Professional Summary Diligent worker who displays many aspects of efficiency and excellency. (livecareer.com)
Hiring talented people who are trustworthy and diligent workers makes delegating tasks easier. (acquirent.com)