WASHINGTON (Reuters) - President Barack Obama gave the United States' top civilian honor on Tuesday to musician Bob Dylan, novelist Toni Morrison and 11 other people he described as his heroes because of their powerful words, songs and actions.

"What sets these men and women apart is the incredible impact they have had on so many people - not in short, blinding bursts, but steadily, over the course of a lifetime," Obama said, presenting the Presidential Medal of Freedom awards in a packed ceremony at the White House.

"They have enriched our lives and they have changed our lives for the better," he said.

In addition to famous political figures such as former U.S. Secretary of State Madeleine Albright and Israeli President Shimon Peres, Obama honored several lesser-known individuals for their work in civil rights and public health.

He recalled reading about one of the award winners, labor activist Dolores Huerta, when he was starting off as a community organizer and said that honoree John Doar, a senior official at the Justice Department during the 1960s, laid the groundwork for U.S. racial equality and voting rights.

"And I think it's fair to say that I might not be here had it not been for his work," Obama, the first black U.S. president, told the audience in the East Room.

He also praised recently retired University of Tennessee women's basketball coach Pat Summitt for being an inspiration to his hoops-loving daughters as well as a brave advocate for those who, like her, are suffering from Alzheimer's disease.

"Anybody who feels sorry for Pat will find themselves on the receiving end of that famous glare, or she might punch you," he said, to laughter.

The other honorees present included William Foege, who led the successful battle to eradicate smallpox disease, Gordon Hirabayashi, who fought Japanese-American internment during World War Two, astronaut and former Senator John Glenn, and retired Supreme Court Justice John Paul Stevens.

Obama also gave the Presidential Medal of Freedom to two people who have died - Girl Scouts founder Juliette Gordon Low and Jan Karski, an officer in the Polish underground who carried his eyewitness account of Nazi atrocities to the outside world.

Peres did not attend the ceremony but will receive his award at a separate event, the White House said.

The president chooses the honorees.

"So many of these people are my heroes individually," Obama said during the ceremony, recalling how he read Morrison's novel "Song of Solomon" as a young man when he was "not just trying to figure out how to write, but also how to be and how to think."

"And I remember in college listening to Bob Dylan and my world opening up because he captured something about this country that was so vital," he said. "Everybody on this stage has marked my life in profound ways."

A pianist from the Marine Corps Band played Dylan's 1963 hit "Don't Think Twice, It's Alright" before the ceremony started. The musician drew loud applause when he received the award in sunglasses and without showing emotion.

When it came time for Morrison to accept her medal, the acclaimed novelist smiled and embraced the president.

Past recipients of the Presidential Medal of Freedom include former U.S. Secretary of State Henry Kissinger, South African anti-apartheid leader and former President Nelson Mandela, and slain civil rights activist Martin Luther King Jr.