Target CEO and chairman Gregg Steinhafel announced his resignation from the company Monday effective immediately, marking the latest and most prolific casualty stemming from last year's data breach.

Steinhafel, who worked with the No. 3 U.S. retailer for over 35 years, revealed in a letter Monday that he would also be stepping down from the company's board. Target CFO John Mulligan replaces Steinhafel as interim president and chief executive and Target board of directors member Roxanne S. Austin has been appointed interim non-executive chair of the board.

Steinhafel's resignation isn't too big of a surprise given that he became the face of Target in the aftermath of last year's data breach. It was revealed in December that cyber thieves had made off with the personal records of over 100 million Target shoppers, including 40 million credit cards. Both Target's and Steinhafel's statements Monday included mentions of the breach, indicating it was definitely a factor in the resignation decision.

"From the beginning, I have been committed to ensuring Target emerges from the data breach a better company, more focused than ever on delivering for our guests," Steinhafel said. "We have already begun taking a number of steps to further enhance data security, putting the right people, processes and systems in place. With several key milestones behind us, now is the time for new leadership at Target."

"Establishing a clear path forward for Target following the data breach has been my top priority. I believe Target has a tremendous opportunity to take the lessons learned from this incident and enhance our overall approach to data security and information technology," Steinhafel said in a recent company statement.

The breach, also the largest theft of retail data ever, has claimed other top-level Target executives over the past few months as well. Chief information officer Beth Jacobs resigned in March and was replaced by Bob DeRodes in late April.

The Target security breach has put cybersecurity in the headlines, with both the public and private sector taking greater interest. Target recently announced that it would be switching over to a new type of credit card in order to prevent such a heist from happening again.

"Target has long been an advocate for the widespread adoption of chip-and-PIN card technology," said Target CFO John Mulligan. "As we aggressively move forward to bring enhanced technology to Target, we believe it is critical that we provide our REDcard guests with the most secure payment product available. This new initiative satisfies that goal."