Walmart's chief technology officer, Jeremy King, is leaving the company, according to a memo obtained by CNBC.

King's role has been to revamp the company's technology presence as it looks to compete with e-commerce rivals, namely Amazon. Of late, Walmart is billing itself as a technology company, and not just a retailer, but it has struggled to rebrand itself as more consumers are flocking to the web and mobile to purchase goods ranging from clothing to medicines.

"People all have their own perceptions of Walmart," King told CNBC, ahead of a recent panel at the SXSW conference, about his role leading Walmart Labs, the retailer's technology arm. "For years now ... I've wanted people to understand we are building a tech organization," he said. "I've got a machine learning team. We have some of the best apps in the world."

King hasn't announced his next role, but the memo did state that he'll be starting a "new adventure" soon. It also notes that Fiona Tan, currently the senior vice president of customer technology, will be stepping up into an "elevated role."

King's last day with the company is March 29.

Walmart declined to comment beyond the memo.

Read the full memo here: