The Georgia congressman was the youngest and last survivor of the Big Six civil rights activists, a group led by Martin Luther King Jr.
House Speaker Nancy Pelosi confirmed Mr Lewis’s death on July 17, calling him “one of the greatest heroes of American history”.
Mr Lewis was mourned, revered and celebrated as an American hero at Atlanta’s Ebenezer Baptist Church, a sacred place for many of those who helped to shape civil rights history.
Three former presidents including Mr Obama joined in the eulogies after nearly a week of mourning that took him from his birthplace in Alabama to the nation’s capital of Washington to his final resting place in his home of Atlanta.
Mr Lewis was “a man of pure joy and unbreakable perseverance”, said Mr Obama during a fiery speech in which he hearkened back to Mr Lewis’ legacy and connected it to the ongoing fight against those who are “doing their darndest to discourage people from voting”.
“He as much as anyone in our history brought this country a little bit closer to our highest ideals,” Mr Obama said.
“And some day when we do finish that long journey towards freedom, when we do form a more perfect union, whether it’s years from now or decades or even if it takes another two centuries, John Lewis will be a founding father of that fuller, fairer, better America.”
Former president George W Bush said Mr Lewis preached the Gospel and lived its ideals, “insisting that hate and fear had to be answered with love and hope”.
Mr Lewis crossed the Edmund Pettus Bridge in Selma, Alabama for the last time on July 26.
The Speaker of the House, Ms Pelosi recalled how Mr Lewis’ body was lying in state at the US Capitol earlier this week, and a double rainbow appeared.
“There was this double rainbow over the casket,” she said. “He was telling us, ‘I’m home in heaven, I’m home in heaven.’ We always knew he worked on the side of angels, and now he is with them.”
The arc of Mr Lewis’ legacy of activism was once again tied to Ebenezer’s former pastor Martin Luther King Jr, whose sermons Mr Lewis discovered while scanning the radio dial as a 15-year-old boy growing up in then-segregated Alabama.
Mr King continued to inspire Mr Lewis’ civil rights work for the next 65 years as he fought segregation during sometimes bloody marches, Greyhound bus “Freedom Rides” across the South and later during his long tenure in the US Congress.
“Get in good trouble, necessary trouble, and help redeem the soul of America,” Mr Lewis said of his run-ins with the law. The phrase was repeated several times during the funeral.
“We will continue to get into good trouble as long as you grant us the breath to do so,” one of Mr King’s daughters, the Rev Bernice King, said as she led the congregation in prayer.
Additional reporting by PA Media.