Just more than half of U.S. workers—51%—said they were satisfied with their jobs in 2017, the highest level since 2005, according to a new report from The Conference Board, a business-research group.

Over the past seven years, Americans report feeling better about their pay along with a greater sense of job security, both features of an economy with a low unemployment rate and a long decline in layoffs. In July, jobless claims continued an extended post-recession slide and hit their lowest level in nearly 50 years.

Workers...