The announcements rounded out the top tier of the team that will advise the incoming chief executive on foreign and national security issues in an era marked by wars in Iraq and Afghanistan and terrorism around the globe.
"I assembled this team because I am a strong believer in strong personalities and strong opinions," he said.
"I think that's how the best decisions are made. One of the dangers in a White House, based on my reading of history, is that you get wrapped up in group-think and everybody agrees with everything and there's no discussion and there are no dissenting views. So I am going to be welcoming a vigorous debate inside the White House."
"But understand, I will be setting policy as president. I will be responsible for the vision that this team carries out, and I will expect them to implement that vision once decisions are made."
Obama's announcements marked a shift in emphasis after a spate of appointments last week for his economic team, led by Timothy Geithner as treasury secretary.
He now has selected half the members of his Cabinet, and is filling out the top echelons of his administration at an unusually quick pace during his transition as he seeks to fulfill his goal of being able to "hit the ground running" when he takes the oath of office on Jan. 20.
Obama said his appointees "share my pragmatism about the use of power, and my sense of purpose about America's role as a leader in the world."
He introduced Clinton first, saying of his former presidential rival, "She possesses an extraordinary intelligence and toughness, and a remarkable work ethic. ... She is an American of tremendous stature who will have my complete confidence, who knows many of the world's leaders, who will command respect in every capital and who will clearly have the ability to advance our interests around the world."
"I am proud to join you ... and may God bless you and our great country," the former first lady said in a brief turn at the lectern.
Gates' presence in Chicago made him a visible symbol of the transition in power from the old administration to the new.
The president-elect, reprising a campaign vow, said he would give the military a new mission as soon as he takes office: "responsibly ending the war in Iraq through a successful transition to Iraqi control." In his announcement remarks, he did not mention his oft-repeated pledge to withdraw most U.S. combat troops within 16 months, although he referred to it in response to a question several moments later.
Obama said he would make Rice, his pick for the U.N., a member of the Cabinet, an increase in stature from the Bush era.
Clinton, Holder, Napolitano and Rice all require confirmation by the Senate.
Jones, as a White House official, does not. Nor does Gates, already confirmed to his post.
At a news conference, Obama expressed sympathy for the victims of the terror attacks in Mumbai but declined to say whether the Indian government would be justified in pursuing terrorists in next-door Pakistan.
"This is one of those times when I have to reiterate there is one president at a time," he said. "We're going to be engaged in some very delicate diplomacy in the next days and weeks, and I think it would be very inappropriate of me to comment."
Obama drew criticism during the campaign when he said the United States would be justified in pursuing al-Qaida terrorists in Pakistan if it had "actionable intelligence."
In a debate on Feb. 26, then-candidate Clinton said of Obama, "Last summer, he basically threatened to bomb Pakistan, which I don't think was a particularly wise position to take."