A top executive at Apple who was a close associate of Steve Jobs said on Thursday that he had thrown himself into negotiations with the major publishing houses as Apple entered the e-book market because “Steve was near the end of his life.”

The executive, Eddy Cue, Apple’s lead negotiator with the publishers, said he was determined to close deals that would allow them to sell their e-books on Apple’s iBookstore in time for the introduction of the iPad in early 2010.

“I wanted to be able to get that done in time for that because it was really important to him,” Mr. Cue said, referring to Mr. Jobs. He was testifying in Federal District Court in Manhattan in the civil antitrust trial brought against Apple by the Justice Department.

“I pride myself on being successful, but this had extra meaning to me,” Mr. Cue added.

Those sped-up negotiations attracted the attention of the government, which filed a lawsuit against Apple and five publishers in April 2012. Mr. Jobs, the co-founder of Apple, died of cancer in October 2011.