The chief executive of NBCUniversal, Jeff Shell, is departing the company after an investigation into inappropriate conduct, Comcast announced Sunday.

In a brief statement, Mr. Shell said Sunday would be his last day after what he called “an inappropriate relationship with a woman in the company.”

“I’m truly sorry I let my Comcast and NBCUniversal colleagues down, they are the most talented people in the business and the opportunity to work with them the last 19 years has been a privilege,” Mr. Shell said.

Comcast, the parent company of NBCUniversal, hired outside counsel to conduct an investigation after a complaint was filed by the woman involved in the relationship, CNBC reported.

“We are disappointed to share this news with you,” the CEO of Comcast, Brian Roberts, said in a separate statement. “We built this company on a culture of integrity. Nothing is more important than how we treat each other. You should count on your leaders to create a safe and respectful workplace. When our principles and policies are violated, we will always move quickly to take appropriate action, as we have done here.”

Mr. Shell has led NBCUniversal since 2020. He has been with the company since 2004. Comcast made no mention of who will succeed him, and said in a company email that Mr. Shell’s team would be reporting to Comcast’s president, Mike Cavanaugh for the time being.