Kennedy was elected in 1960, winning Illinois by less than 9,000 votes. But the powerful Democratic organization in Chicago helped give him a wide margin of victory in Cook County.
Just a week after his death, the Chicago City Council renamed the northwest expressway the John F. Kennedy Expressway.
On Friday, Mayor Rahm Emanuel remembered the late president in a speech to hundreds of Chicago Public Schools students.
"We remember John F. Kennedy today, not because his death was tragic, which it was. But because his life was so extraordinary," Emanuel said.
President Kennedy was the first to bring jazz to the White House. So there were jazz performances during Friday's event for CPS students.
Many Americans reflected on where they were when they heard the news that President Kennedy had been assassinated.
Bells marked the moment five decades past. Those old enough remember exactly where they were when they heard. Nilsa Miranda remembers the principal at Lakeview High announcing something awful has happened.
"We all cried. We were hugging each other, and we were sad," Miranda said.
Mel Funchess was a freshman at Provison East.
"That stuck with me because other things seemed so small, so irrelevant," he said.
"He dreamed for a better world for all mankind, did he not?" said Ald. Ed Burke, 14th Ward.
Burke, who led a Kennedy tribute Friday, was in college in 1963 and happened to be in a car with Richard M. Daley when they heard the bulletin.
"We heard it driving home, but we came back and watched it like everyone else," said the former Mayor Daley.
Everyone watched - in disbelief - particularly in the Daley household.
"My father, of course, my mother, we said a prayer. I remember our family said a prayer," said Daley. "It was like having a son in the family die. That's how my father felt about him."
The then-mayor Richard J. Daley had been an admirer and powerful supporter of the young president and saw great promise in the new frontier and Kennedy's invitation to younger generations to invest in public service.
"I think he had a huge effect on all of us - about what government should be, what politics should be and how we should get involved," Richard M. Daley said. "I think JFK built confidence in America, confidence. We need confidence today. We just don't have enough confidence."
The students at CPS' John F. Kennedy High School on the Southwest Side only know of him as a part of a chapter in a history book.
"I knew he was a president and he did something obviously special for a school to be named after him," said student Naomi Ford.
Students talked about the slain president as a way to mark the 50th anniversary of his assassination through videos and excepts of his speeches.
"One of our themes is having pride in our school, being positive, respectful, filled with integrity, determined and striving for excellence. I think that mantra exemplifies this president," said Principal George Szkapiak.
And while many of these teens' parents weren't born until after President Kennedy's assassination, substitute teacher Carol Anne Peterman was. She was in fifth grade.
"There was crying all over the school. And when we got home everyone was very solemn," she said.
Social studies teacher Sara White and other teachers shared Kennedy's accomplishments, like being the first Catholic president, civil rights and the Cuban Missile Crisis.
"Every generation has a battle that they need to conquer," White said.
There was a moment of silence in honor of President Kennedy. but for senior Raymond Hernandez, the school day was more than just a history lesson.
"It was really nice to hear how it was back then," he said.
The nation solemnly marked the 50th anniversary of President John F. Kennedy's assassination Friday with subdued remembrances at Kennedy's grave and the infamous site in downtown Dallas where the young, glamorous president was gunned down in an open-top limousine.
Dallas Mayor Mike Rawlings says the nation grew up on the day Kennedy died and had to live up to the challenges of the words and vision of a beloved president. Rawlings says Dallas has turned "civic heartbreak" into hard work and it is a much different place today.
He called Kennedy an "idealist without illusions who helped build a more just and equal world."
A new marker being unveiled in Dallas' Dealey Plaza will feature the last paragraph of a speech President John F. Kennedy was set to give 50 years ago.
Kennedy's motorcade was en route to a luncheon at the Dallas Trade Mart when he was assassinated.
The speech was to have ended with Kennedy noting that Americans are "watchmen on the walls of world freedom" and therefore must strive to be worthy of that power and try to achieve peace.
Ruth Altshuler chairs the committee that organized the city's event marking the 50th anniversary of the assassination. She says the marker will be "very dignified and very tasteful and very meaningful."
Flags flew at half-staff, and moments of silence were planned for the hour when Kennedy was shot riding in a motorcade. The quiet reverence extended across the Atlantic Ocean to his ancestral home in Ireland.
Shortly after sunrise, Attorney General Eric Holder paid his respects at Kennedy's recently refurbished grave at Arlington National Cemetery, where a British cavalry officer stood guard, bagpipes played and a flame burned steadily as it has for the last half-century.
About an hour later, Jean Kennedy Smith, 85, the last surviving Kennedy sibling, laid a wreath at her brother's grave, joined by about 10 members of the Kennedy family. They clasped hands for a short, silent prayer and left roses as a few hundred onlookers watched.
Dallas was bitterly cold, damp and windy, far different from the bright sunshine that filled the day Kennedy died.
About 5,000 tickets were issued for the free ceremony in Dealey Plaza, which is flanked by the Texas School Book Depository building where sniper Lee Harvey Oswald perched on the sixth floor.
A stage for the memorial ceremony, just south of the depository building, was backed with a large banner showing Kennedy's profile. Video screens showed images of Kennedy with his family.
People began assembling for the event hours ahead of time.
"President Kennedy has always been kind of revered in our family," Colleen Bonner, 41, of suburban Hurst, said. "I just wanted to honor his memory, and I wanted to be a part of history."
The U.S. Naval Academy Men's Glee Club performed at the ceremony in a nod to Kennedy's military service, as was an Air Force flyover. A moment of silence was held at 12:30 p.m., when the president was shot.
Numerous events were held around Dallas this year to mark the anniversary, including panels of speakers who were there that day, special concerts and museum exhibits.
In Boston, Gov. Deval Patrick and Maj. Gen. Scott Rice of the Massachusetts National Guard endured a heavy rain during a wreath-laying ceremony at the Kennedy statue on the front lawn of the Statehouse. The statue, dedicated in 1990, has been largely off-limits to public viewing since security procedures put in place after the 9/11 terrorist attacks. But the area was opened to visitors Friday.
Both of Kennedy's grandfathers served in the Massachusetts Legislature and in January 1961 the president-elect came to the Statehouse to deliver one of his most famous addresses, which came to be known as the "City on a Hill" speech, just before leaving for his inauguration in Washington.
Earlier Thursday, in Dublin, a half-dozen Irish soldiers toting guns with brilliantly polished bayonets formed a guard of honor outside the U.S. Embassy as the American flag was lowered to half-staff. An Irish army commander at the embassy drew a sword and held it aloft as a lone trumpeter played "The Last Post," the traditional British salute to war dead. A bagpiper played laments including "Amazing Grace." A U.S. Marine raised the flag again as the bugler sounded an upbeat "Reveille."
More than a dozen retired Irish army officers who, as teenage cadets, had formed an honor guard at Kennedy's graveside gathered in the front garden of the embassy in the heart of the Irish capital to remember the first Irish-American to become leader of the free world.
Together with Irish Foreign Minister Eamon Gilmore and embassy staff, they observed a minute's silence and laid two wreaths from the Irish and American governments in memory of JFK.
The former cadets invited by Jacqueline Kennedy to serve as the graveside honor guard described the awe - and fear - they experienced as they traveled to the United States 50 years earlier.
"We were young guys, all pretty much 18. We had no passports, no visas. None of us had flown before," said retired Col. Brian O'Reilly, 68. "We were told on the Saturday night we were wanted for the funeral. The next day, we were on the plane with our own president (Eamon de Valera) heading for Washington."
The day of the funeral was crisp and windless, with trees full of autumn leaves and a cloudless blue sky, the sun blindingly low on the horizon.
The Associated Press contributed to this report.