We looked through Walmart CEO Doug McMillon's social media, and we can see why he earned the title 'most connected CEO'

While most CEOs are hard to track down online, McMillon has an informative Wikipedia page.

The page features a high-quality photo, a detailed description of his early life, work history (most of it at Walmart), education, and personal life.

McMillon opted to use Facebook, Instagram, and LinkedIn, but not Twitter (although Walmart itself has a Twitter account).

The Brunswick study mentions that verification was one of the factors they used to determine which CEOs had a stronger social media presence.

According to the study, "People are 3 times more engaged with Connected Leaders on Instagram than Facebook and Twitter."

McMillon has chosen both Instagram and Facebook as his main social media accounts, and posts there more regularly than on LinkedIn (the latter was the preferred platform of other CEOs on the list).

For his 30,800 Instagram followers, McMillon chooses to tell personal stories that show what he's really like. In this post, for example, he shared an old photo and a new one — the classic "then and now."

McMillon pays close attention to his employees — especially the ones on the ground.

His Instagram posts feature Walmart employees from around the globe. The employee in the green shirt standing with McMillon is a store manager in Shenzhen, China.

In addition to traveling around the world on store visits, McMillon talks to his employees to get a sense of their personal stories. He's shared dozens of their anecdotes online over the years.

McMillon's 103,140 Facebook followers usually get the same posts his Instagram followers do, but sometimes he adds in a few extras. In this video, McMillon takes KITT, the robo-car from the TV show "Knight Rider," out for a spin.

He gets a similar number of likes on Facebook and Instagram (around 1,000 on average), but he typically gets double the comments from his Facebook followers.

McMillon frequently mentions that he began his working life as a summer associate at Walmart in 1985, when he was still in high school. And, indeed, his LinkedIn work history shows it.

According to the study, 44% of CEOs have a LinkedIn presence, but only 45% of those CEOs actually post on it. It seems that part of McMillon's success is that he uses social media on a daily basis, which gives him the opportunity to promote his business more than any other CEO.

McMillon reshares posts and articles on LinkedIn once or twice a week, but he also writes his own articles.

To date, he's written five, about everything from Walmart's sustainability program to the time he held a company-wide contest.

As an avid Hot Wheels enthusiast, McMillon challenged each store to sell as many toy cars as possible. Whoever sold the most would have their actual car washed by McMillon himself. And, in the end, a store manager in Carolina, Puerto Rico, got his car personally washed by the CEO.

The CEO added: "Social media gives me a way to see that impact live, recognize their great work and simply say 'thank you.' That's one of the best things about my job: I get to tell the world about the innovative and meaningful things our people are doing every day."