When Linda Mason SOM ’80 was a student at the Yale School of Management, she said she never imagined that over 20 years after graduation she and her husband, another SOM graduate, would found a company that could be the poster-child for the school.

The creation of Mason, a former Yale Corporation member, and her husband Roger Brown SOM ’82, Bright Horizons Family Solutions, the world’s leading provider of employee-sponsored child-care and early education, was recently named for the sixth time to FORTUNE magazine’s “100 Best Companies to Work For” list. The annual ranking is designed to recognize those employers who have created workplaces considered to be the best in the nation. CarMax, the country’s top specialty retailer of used cars, was also named to the list. The company was founded and headed by another member of Mason’s graduating class, Austin Ligon SOM ’80.

The list was determined by a confidential, random survey of associates of the companies and an evaluation of the company’s culture, compensation, training and turnover rates, the magazine said.

SOM Deputy Dean Stan Garstka said Lignon and Mason demonstrate the power of the socially responsible management model espoused by SOM.

“In both instances they are at the top of very competitive industries because ethical business behavior and respect for customers and employees does indeed generate shareholder value,” he said.

Mason, for one, said she could not have gotten to the place she is now — namely the head of a firm that operates more than 500 workplace childcare centers in 37 states and four countries — were it not for the education she received at the School of Management.

“There was an incredible atmosphere of using enterprise to have an impact on society,” Mason said, reflecting on her time at the school.

She added that SOM connections have proved fruitful during her career. Bright Horizons’ first client was another SOM classmate, and past SOM Dean William Donaldson ’53 joined the Bright Horizons board.

Bright Horizons was founded in 1986 after the couple returned from Sudan, where they spearheaded the formation of a Save the Children chapter. Upon their return to the United States, Mason said they began formulating a plan to create a mission-driven corporation that affected young children. They soon found a space in the childcare field.

“We were looking to create an organization where childcare professionals are valued and that would translate into excellent care for children,” Mason said.

Mason attributed the company’s ranking in FORTUNE to Bright Horizon’s focus on building a stimulating internal culture for their workers.

“We really value and respect teachers for what they do and focus on the individual,” Mason said. “We hire people who are very mission-driven and focused on equality, and it really becomes self-renewing as they hire similar individuals.”

While Mason remains the chairman of the company and has expanded into several nonprofit endeavors as well, Brown has since become president of Berklee College of Music.

Ligon, who could not be reached for comment, said in a press release last week said that he recognizes how unusual it seems for a used car company to be named as one of the greatest places to work.

“Many FORTUNE readers will wonder how a company that sells cars, especially used cars, can be a great place to work. It’s really pretty simple. By breaking the traditional industry approach and creating a customer-friendly, transparent, high-integrity selling process, we have cracked the code on how to make car buyers happy,” he said in the release.

Ligon added that his company has a competitive advantage because they are ethical and trustworthy.

“The combination of a high-integrity process and happy customers helps us attract great associates who create a great working environment,” he said. “It’s a virtuous circle.”