Target Chairman, President and CEO Gregg Steinhafel said in a statement released to The Associated Press that the company will search for an interim chief information officer who can help guide the company through the transformation.
Jacob had been in her current role since 2008 and oversaw teams in the U.S. and India.
Target disclosed on Dec. 19 that the data breach compromised 40 million credit and debit card accounts between Nov. 27 and Dec. 15. Then on Jan. 10 it said hackers also stole personal information - including names, phone numbers as well as email and mailing addresses - from as many as 70 million customers.
Target, based in Minneapolis, also plans to look outside the company for a chief information security officer and a chief compliance officer. Before the overhaul, information security functions were split among a variety of executives. Target's new chief information security officer will centralize those responsibilities, the company said.
The previous duties of chief compliance officer were overseen by Target's current vice president of assurance risk and compliance, who had previous plans to retire at the end of March. Now, Target is separating the responsibility for assurance risk and compliance.
Target also says it's working with an outside adviser, Promontory Financial Group, to help it evaluate its technology, structure, processes and talent as part of the overhaul.
"While we are still in the process of an ongoing investigation, we recognize that the information security environment is evolving rapidly," Steinhafel said in a statement.
Target is still grappling with the fallout of the theft. The company said last week that its profit for the fourth quarter fell 46 percent on a revenue decline of 5.3 percent as the breach scared off customers.
While Target said sales have been recovering since it disclosed the breach in mid-December, the company expects business to be muted for some time. It issued a profit outlook for the current quarter and full year that was below Wall Street estimates.
The company is offering free credit monitoring for a year for any customer shopping at a Target store who wants it.
It's also equipping its locations with more security technology. Target is accelerating its $100 million plan to roll out chip-based credit card technology, which experts say is more secure than using traditional magnetic stripe cards.
When the final tally is in, Target's breach may eclipse the biggest known data breach at a retailer, one disclosed in 2007 at the parent company of TJ Maxx that affected 90 million records.
In a posting last week on a company blog, Steinhafel said, "In the weeks ahead, we hope to understand more about how this attack happened. And will use what we learn to inform our guests, make Target a safer place to shop and to drive change across the broader retail industry."
In a letter to Steinhafel furnished by Target, the outgoing Chief Information Officer Jacob said resigning was a "difficult decision," but she said that "this was a time of significant transformation for the retail industry and for Target." She did not mention the data breach.