JPMorgan has replaced 2 million credit and debit cards as a result of the breach, said Dimon in his first public comments about the event. The bank has replaced nearly all the affected cards.
JPMorgan is the world's largest issuer of credit cards.
Dimon expects that cybercrimes such as the Target breach will become more common if retailers and banks do not work on security, he said.
"This story is not over, unfortunately," Dimon said in a conference call with investors following the bank's fourth-quarter earnings announcement.
In December, Target said 40 million credit and debit card accounts - including customers' card numbers, expiration dates, debit-card PINs and the embedded code on the magnetic strip on the back of cards- were stolen in a data breach that happened between Nov. 27 and Dec. 15. Last week, the company disclosed that hackers stole an additional trove of data affecting 70 million people. That data included names and phone numbers as well as email and mailing addresses. The company said there is some overlap between the two data sets.
It is the second-largest theft of shoppers' credit card data, following the theft of 90 million customers' data from discount retailer TJX in 2007.
Dimon said the bank hasn't seen a reduction in consumer spending due to the breach, and there are no signs that consumers moved to other forms of payment, like cash or checks. The breach is not expected to affect JPMorgan's financial results, a company spokeswoman said.
Dimon, who had not publicly commented on Target's breach until Tuesday, said he expects that banks will issue cards with more security features on them in the future.
Banks and the stores that accept their credit and debit cards have had a complicated relationship for years.
Stores want to accept credit and debit cards because it's often a customer's preferred form of payment. But every time a shopper swipes a credit or debit card, a bank charges a small fee. That fee, known as an interchange fee, adds up to billions of dollars in revenue for the banks. It's why stores like gas stations charge customers more to use credit or debit cards versus cash.
"This might be a chance for retailers and banks, for once, to work together as opposed to suing each other like we've been doing the last decade," Dimon said.