Boxer, philanthropist and social activist Muhammad Ali

Muhammad Ali is one of the most famous boxers of all time. His conversion to Islam and draft evasion conviction surrounded him with controversy and even exile from boxing for three years. Despite the hiatus, his quick reflexes and strong punches helped Muhammad Ali become the first person in history to win the heavyweight champion title three times. At the lighting ceremony at the 1996 Olympics, Muhammad Ali showed the world his strength and determination in dealing with the debilitating effects of Parkinson's syndrome.

Boxer, philanthropist and social activist Muhammad Ali was born Cassius Marcellus Clay Jr. on January 17, 1942 in Louisville, Kentucky. Considered one of the greatest athletes in boxing history,
Ali showed at an early age that he wasn't afraid of any bout—inside or outside of the ring. Growing up in the segregated South, Ali experienced racial prejudice and discrimination firsthand, which likely contributed to his early passion for boxing.
At the age of 12, Ali discovered his talent for boxing through an odd twist of fate. His bike was stolen, and Ali told a police officer, Joe Martin, that he wanted to beat up the thief. "Well, you 
better learn how to fight before you start challenging people," Martin reportedly told him at the time. In addition to being a police officer, Martin also trained young boxers at a local gym.

Ali started working with Martin to learn how to box, and soon began his boxing career. In his first amateur bout in 1954, he won the fight by split decision. Ali went on to win the 1956 Golden Gloves tournament for novices in the light heavyweight class. Three years later, he won the National Golden Gloves Tournament of Champions, as well as the Amateur Athletic Union's national title for the light-heavyweight division

In 1960, Ali won a spot on the U.S. Olympic boxing team. He traveled to Rome, Italy, to compete. At 6 feet 3 inches tall, Ali was an imposing figure in the ring. He was known for his footwork, and for possessing a powerful jab. After winning his first three bouts, Ali then defeated Zbigniew Pietrzkowski from Poland to win the gold medal.
After his Olympic victory, Ali was heralded as an American hero. He soon turned professional with the backing of the Louisville Sponsoring Group. During the 1960s Ali seemed unstoppable, winning all of his bouts with majority of them being by knockouts. He took out British heavyweight champion Henry Cooper in 1963 and then knocked out Sonny Liston in 1964 to become the heavyweight champion of the world.
Often referring to himself as "the greatest," Ali was not afraid to sing his own praises. He was known for boasting about his skills before a fight and for his colorful descriptions and phrases. In one of his more famously quoted descriptions, Ali told reporters that he could "float like a butterfly, sting like a bee" in the boxing ring.
The day after the championship bout with Liston, Muhammad Ali publicly announced his conversion to Islam. The public was not happy. Ali had joined the Nation of Islam, a group led by Elijah Muhammad that advocated for a separate black nation. Since many people found the Nation of Islam's beliefs to be racist, they were angry and disappointed that Ali had joined them.
Up to this point, Muhammad Ali was still known as Cassius Clay. When he joined the Nation of Islam in 1964, he shed his "slave name" (he had been named after a white abolitionist that had freed his slaves) and took on the new name of Muhammad Ali.
Returning to the ring in 1970, Ali won his first bout after his forced hiatus. He knocked out Jerry Quarry in October in Atlanta. The following year, Ali took on Joe Frazier in what has been called the "Fight of the Century." Frazier and Ali went for 15 rounds before Frazier briefly dropped Ali to the ground, before beating Ali by decision. Ali later beat Frazier in a 1974 rematch.
Another legendary Ali fight took place in 1974. Billed as the "Rumble in the Jungle," the bout was organized by promoter Don King and held in Kinshasa, Zaire. Ali fought the reigning heavyweight champion George Foreman. For once, Ali was seen as the underdog to his younger, powerful opponent. Ali silenced his critics by defeating Foreman and once again becoming the heavyweight champion of the world.
Perhaps one of his toughest bouts took place in 1975 when he battled longtime rival Joe Frazier in the "Thrilla in Manila" fight. Held in Quezon City, Philippines, the match lasted for more than 14 rounds with each fighter giving it their all. Ali emerged victorious in the end.
By the late 1970s, Ali's career had started to decline. He was defeated by Leon Spinks in 1978 and was knocked out by Larry Holmes in 1980. In 1981, Ali fought his last bout, losing his heavyweight title to Trevor Berbick. He announced his retirement from boxing the next day.
In his retirement, Ali has devoted much of his time to philanthropy. He announced that he has Parkinson's disease in 1984, a degenerative neurological condition, and has been involved in raising funds for the Muhammad Ali Parkinson Center in Phoenix, Arizona. Over the years, Ali has also supported the Special Olympics and the Make a Wish Foundation among other organizations.
Muhammad Ali has traveled to numerous countries, including Mexico and Morocco, to help out those in need. In 1998, he was chosen to be a United Nations Messenger of Peace because of his work in developing countries.
In 2005, Ali received the Presidential Medal of Freedom from President George W. Bush. He also opened the Muhammad Ali Center in his hometown of Louisville, Kentucky, that same year. "I am an ordinary man who worked hard to develop the talent I was given," he said. "I believed in myself and I believe in the goodness of others," said Ali. "Many fans wanted to build a museum to acknowledge my achievements. I wanted more than a building to house my memorabilia. I wanted a place that would inspire people to be the best that they could be at whatever they chose to do, and to encourage them to be respectful of one another."
Despite the progression of his disease, Ali remains active in public life. He embodies the true meaning of a champion with his tireless dedication to the causes he believes in. He was on hand to celebrate the inauguration of the first African-American president in January 2009 when Barack Obama was sworn-in. Soon after the inauguration, Ali received the President's Award from the NAACP for his public service efforts.
As he has done every year since its inception, Ali hosted the 15th Annual Celebrity Fight Night Awards in Phoenix in March 2009. The event benefited the Celebrity Fight Night Foundation and the Muhammad Ali Parkinson Center.
Ali has been married to his fourth wife, Yolanda, since 1986. The couple has one son, Asaad, and Ali has several children from previous relationships, including daughter Laila who followed in his footsteps for a time as a professional boxer.