“The workplace is where real social change begins,” Taylor said. “HR professionals are the center of all people hope for and aspire to. Unlike any other profession, we create workplaces that change lives.”

His message of inclusivity fit with this year's conference theme, “Creating Better Workplaces,” as well as SHRM's new tagline, “Better workplaces, better world.”

Taylor's keynote included profiles of individuals representing some of these overlooked populations. Among them was Alice Lee Jones, who, after being sentenced to life in prison for a one-time drug offense, was released and given a second chance. She represents the one in three Americans with a criminal record.

Creating new opportunities for those with a criminal past is the heart of SHRM's new Getting Talent Back to Work initiative, which asks employers to open their minds and make an effort to welcome reformed criminals. “People who have paid their debt to society, who want to work and who are qualified for the job should not be re-sentenced to joblessness,” Taylor said.

Another overlooked source of talent? People with disabilities, including those with physical or developmental disabilities, as well as intellectual, or even unseen. “Not all disabilities are visible,” Taylor said, noting conditions such as ADHD or depression. “People bring challenges to work that are much broader than disability.”

When you make a place in your company for people with disabilities, not only are you expanding your talent pool, but as pointed out by one guest, you're showing all of your employees that empathy is a part of the company culture.

Taylor also hit on the importance of returning veterans, who are often discriminated against during the hiring process. There resumes look different but “they have skills you can't find anywhere else,” Taylor said.

The last group Taylor called out was one that will see increasing attention in the coming years: older adults. These job seekers often hear that they are “overqualified” or “unable to adapt,” which are just diplomatic ways of saying they're too old.

“Age discrimination starting to affect Gen X,” Taylor said, expounding on the talents and wealth of expertise that comes with an experienced working population. “We miss out on the mentoring and idea exchange that only comes from a multi-generational workforce.”

Taylor stressed that he's not suggesting that HR professionals go out and hire someone for a position they're not right for just because they fit into one of these categories. But if companies don't change their recruiting strategies to be more inclusive, they'll never realize when they're overlooking key talent. “We need to let these people in,” Taylor said, “We need to create workplaces where everyone can thrive.”

Read more: 

• In today's job market, criminal record less important than employment record
• Large companies' older workers a blessing for small businesses
• More employers seeking veterans as they staff up