John Daggett was a millionaire businessman who tried to take control of Wayne Enterprises with the help of Bane.
History
According to the intelligence agencies, Daggett employed Bane and his mercenaries to secure diamond mining rights in West Africa before bringing them to Gotham City and working with them to acquire Bruce Wayne's fingerprints with help from cat-burglar Selina Kyle. Selina wanted a clean slate tool from Daggett to erase her past, but he told her when she confronted him that it was a myth.
Dagget even funded the construction of Bane's underground base, helping him place bombs over the city and with tasks. One of them was stalling Officer John Blake at the Gotham Stock Exchange to help give way for Bane and his men to escape.
In order for Daggett's attempted takeover of Wayne Enterprises to work, Bane used Bruce's fingerprints so he would break into the Stock Exchange and put down a list of risky investments under Bruce's name, bankrupting him and lowering the company's share value. Bruce was aware of this through Lucius Fox, who knew that Dagget bankrupted him. When Miranda Tate was put in charge of the company instead, Daggett complained to Bane about it, and Bane told Daggett's assistant, Phillip Stryver, to wait outside. He then grabbed Daggett once Stryver was gone and said, "I'm necessary evil," right before ending Daggett's life in an agonizing way. Blake later told James Gordon in the hospital that Daggett's body was found in a dumpster.