King, Martin Luther King Junior's wife, seen by many as the "first lady" of the US civil rights movement, died last week in a Mexican alternative health clinic at the age of 78, after complications from ovarian cancer and a recent debilitating stroke and heart attack.
At the New Birth Missionary Baptist Church in Lithonia on Tuesday, Bush told the funeral service: "By going forward with a strong and forgiving heart, Coretta Scott King not only secured her husband's legacy, she built her own.
"Having loved a leader she became a leader. And when she spoke Americans listened closely, because her voice carried the wisdom and goodness of a life well-lived."
The pews at the 10,000-person capacity church were filled with politicians, members of the entertainment industry and the US civil rights community.
Former presidents Bill Clinton, Jimmy Carter and George Bush Sr also attended the service. Bush and his predecessors sat on the stage behind King's coffin and in front of a large choir.
Tens of thousands of people have mourned King since her death, with an estimated 42,000 people paying their respects as she became the first woman and first African-American to lay in state at the Georgia Capitol building over the weekend.
On Monday, others braved the rain and cold to get a glimpse of King, adorned in pink attire in a champagne and bronze-coloured casket, at the historic Ebenezer Baptist Church, where her husband preached decades ago.
Coretta Scott King(R) died of
King died on 30 January, of bronchial pneumonia at a controversial alternative health centre in Mexico, where she had sought possible treatment for terminal ovarian cancer.
In recent days, her four children said their mother, who established the Martin Luther King Junior Centre for Non-violent Social Change, was making progress recovering from an August stroke. Then she was diagnosed with cancer in November.
Yolanda King, the eldest child, told reporters on Sunday: "We saw a genuine commitment in her life to making a difference. That commitment, that passion we must all find within ourselves."
Civil rights activist
Born 27 April, 1927, near Marion, Alabama, Coretta Scott King played a back-up role in the civil rights movement until her husband was gunned down on a Memphis motel balcony on 4 April, 1968.
Clinton (C) was one of three former
US presidents at King's funeral
Bush said King had known danger, injustice and "terrible grief" and became one of the most admired Americans of her time.
He said: "Rarely has so much been asked of a pastor's wife, and rarely has so much been taken away."
Clinton told reporters on the way to Georgia: "In a larger sense there are millions of people all across America that are the children of Martin and Coretta King, whose whole lives were shaped by their passion for equal opportunity and justice."