Paul Dacre, who was the last Fleet Street editor to go before the inquiry, is to face further questions about his decision to accuse Grant of "mendacious smears" against his paper.
Lord Justice Leveson said today that he wanted to see Dacre appear again this week, adding that it was "not negotiable".
The judge said that he was "extremely unhappy" with the manner in which an "obvious conflict" between Grant and the Daily Mail's publisher Associated Newspapers had continued into the inquiry.
Speaking at the Royal Courts of Justice, he said: "Before we start, I want to say that I am extremely unhappy about the way in which yesterday afternoon did what I perceived to be damage to the appropriate flow of this inquiry.
"I am not willing to allow what is an obvious conflict between one of the core participants and another to divert attention from my concern about the customs, practices and ethics of the press."
Dismissing a request by the lawyer representing Associated Newspapers for Dacre to submit evidence in writing, Leveson said that he would set aside time on Thursday for him to appear again in person.
The conflict stems back to Grant's appearance at the inquiry last November, when the actor said that he could not "think of any conceivable source" other than his voicemails being hacked for a Mail on Sunday article published in 2007 about his phone calls from a Warner Bros employee.
The story claimed that Grant's relationship with his then girlfriend Jemima Khan was in trouble over "late-night phone calls with a plummy-voiced studio executive".
Grant also suggested that the Daily Mail could have obtained "possibly illegal" material about the birth of his daughter from the hospital where she was born.
Dacre responded by accusing Grant in the Daily Mail of "mendacious smears driven by his hatred of the media". He also claimed that Grant was trying to "hijack" the inquiry, and using it as part of a "highly calculated attempt to wound my company".
The Times editor James Harding is appearing again today at the Leveson following the launch of a police investigations over revelations of potential email hacking at the paper.
Dominic Mohan, The Sun's editor, has also been recalled to give further evidence, and will appear later on Tuesday.