Athletes, and boxers, in particular, are notorious for being unable to stay retired. "The Greatest" was no different. While still holding the heavyweight belt in 1979, Ali retired at age 37. He came back the following year to fight, and lose badly to, Larry Holmes. Despite calls for him to retire for good, Ali, seen here in 1983 with President Ronald Reagan, fought one last time on Dec. 21, 1981, losing a 10-round decision to Trevor Berbick.
Ol' Blue Eyes broke more than a few hearts when he decided to call it quits in 1971 at the age of 55. But his disappointed fans didn't have to wait long for his return. Two years later he staged his comeback in a television special that was so successful he didn't hang it up for good until the mid-1990s.
At the peak of his career, and after leading the Chicago Bulls to three straight NBA titles, Jordan walked away from the game in the fall of 1993 to pursue a career in professional baseball. After a mostly forgettable year in the minors, he returned to the Chicago Bulls in the spring of 1995, leading the team to three more championships in 1996-98. While he retired again in early 1999, he made another comeback in 2001, playing two final seasons with the Washington Wizards at age 38.
After announcing in 1994 that she planned to stop touring, Streisand performed her final "farewell" concert in 2000, saying she was done for good. She returned in 2006 with a comeback tour to raise money for her foundation. Since then, she's stuck around and even released a couple new studio albums.
The country music superstar announced his retirement in 2000. His decision to not tour has held for the most part, but he returned to live performances with a five-year residency in Las Vegas starting in December 2009.
Burned out by touring, Osbourne announced the 1993 live album "Live & Loud" would be his final album and dubbed his tour in support of the album "No More Tours," a play on his "No More Tears" album. But by 1995, he was back again, releasing the album "Ozzmosis" and returning to touring, dubbing his concert performances "The Retirement Sucks Tour."
Some athletes find that they miss the game too much to stay retired. Favre was so great that he did so twice, with neither "retirement" lasting more than a few months. First, he retired in March 2008 after 16 seasons with the Green Bay Packers, including a Super Bowl title in 1997. By that summer he had decided he wanted to return and was traded by the Packers to the New York Jets. After one season with the Jets, he again retired, only to come back in the summer of 2009 with the Minnesota Vikings. He led Minnesota to the playoffs in 2009 and returned for a lackluster season in 2010 before retiring for good.
Armstrong won his seventh consecutive Tour de France title in 2005 and retired afterward. He later un-retired in 2008 and would compete in two more Tour de France competitions, finishing third in 2009 and 23rd in 2010. The United States Anti-Doping Agency would disqualify him from those races in 2012 and ban him from cycling for life for doping offenses.
The Los Angeles Lakers star announced on Nov. 7, 1991, that he had tested positive for HIV and was retiring immediately. Johnson initially said that he did not know how he contracted the disease, but later acknowledged that it was through having multiple sexual partners during his playing career. Despite his retirement, Johnson played in the 1992 NBA All-Star Game, earning MVP honors after recording 25 points, nine assists and five rebounds, and attempt an aborted comeback before the 1992-93 season, before actually returning for the last 32 games of the 1995-96 NBA season.
After releasing "The Black Album" in 2003, Jay-Z declared it would be the last album he would ever make. The "retirement" was short-lived, as he continued to work on various side projects and make guest appearances, culminating in his 2006 comeback album "Kingdom Come."
In one of the shortest retirements ever, Bynes announced in June 2010 that she was retiring, tweeting that "I don't love acting anymore, so I've stopped doing it." A month later she had a change of heart and "unretired," later telling People magazine that she was simply taking time off from acting. In the fall of 2012, she again announced her retirement from acting, this time telling People she planned to focus on launching a career as a fashion designer and rapper.
In the summer of 2002, Cher embarked on Living Proof: The Farewell Tour, billed as the final live concert tour of her career, although she vowed to continue making records and films. Originally scheduled for 49 shows, the worldwide tour was extended several times, eventually running for 326 dates and ending in 2005. In 2008, she began a three-year, 200-performance residency at Caesars Palace in Las Vegas, and in September 2013 she announced she would be returning to touring in 2014 with the Dressed to Kill Tour, in support of her her 26th studio album, "Closer to the Truth."
Sugar Ray Leonard
Starting in 1982 when he suffered a detached retina, Leonard set off on a string of retirement-comebacks that saw him retire and unretire a total of four times before hanging up his gloves for good in 1997.
The Oscar-winning actor-director claimed in 2008 that "Gran Torino" would be his last acting role, but that he would continue working behind the camera. He's since directed "Invictus," "Hereafter" and "J. Edgar," but came out of his self-imposed acting retirement to star in 2012's "Trouble with the Curve," directed by Robert Lorenz, who worked with Eastwood as an assistant director on several films.
Whether it was for real or just a publicity stunt, Joaquin Phoenix announced his retirement from acting in 2008 to pursue a career as a rapper. While his supposed career change was filmed for the mockumentary "I'm Still Here," he soon came out of "retirement" for his Oscar-nominated role in Paul Thomas Anderson's 2012 film "The Master."
After starring on the hit show "Lost," Lilly told E! in 2010 that she was retiring from acting when the show wrapped up following its sixth season and just wanted some "quiet space." By the following year she had returned, appearing in the 2011 movie "Real Steel" opposite Hugh Jackman and will also appear in Peter Jackson's second and third films in "The Hobbit" series.
The Pittsburgh Penguins star retired from the NHL following the 1996-97 season. In 1999, he headed up an ownership group that bought the team out of bankruptcy and a year later he came out of retirement to play for his team. He continued playing with the Penguins before ending his career for good in 2006.
After retiring from baseball in 1994, the Chicago Cubs second baseman came back to the team for the 1996 and 1997 seasons.
After initially retiring following the 2003 season, his fifth with the New York Yankees, Clemens signed a one-year deal with his adopted hometown Houston Astros in early 2004 to join close friend and former Yankees teammate Andy Pettitte. He won his seventh Cy Young award in 2004 and after much retirement speculation returned to the team in 2005, helping the Astros to the World Series. After implying that he was retiring for good in 2006, he again returned to the Astros for one final season before wrapping up his career for good with a return to the Yankees in 2007.
Facing a four-game suspension after testing positive for marijuana use, the Heisman Trophy winner and Miami Dolphins running back abruptly retired from the NFL in 2004, instead studying Ayurveda, the ancient Indian system of holistic medicine, at the California College of Ayurveda that fall. He returned to the Miami Dolphins in July 2005, paying back a percentage of his signing bonus and completing his original four game suspension. After being suspended for another NFL drug policy violation in 2006, he played for the Canadian Football League's Toronto Argonauts before returning to the Dolphins for 2007-10. He played one final season for the Baltimore Ravens before retiring again in February 2012.
In 2002, the best-selling author announced that we was retiring due to the pain he continued to suffer from a 1999 accident in which he was almost killed by a van while walking along a Maine road. While the pain limited his writing, he eventually made a comeback, including penning a column for Entertainment Weekly and writing more than a dozen novels since his retirement announcement.
Disenchanted with acting in 1991, Rourke decided to return to boxing, in which he had excelled as an amateur from 1964 to 1973. He was undefeated in eight professional fights, with six wins and two draws, but after a couple years returned to acting.
After roles in "Friday," "Dead Presidents," "The Fifth Element" and "Jackie Brown," Tucker hit paydirt with the hit film "Rush Hour" in 1998. Over the next nine years, he only appeared in "Rush Hour 2" and "Rush Hour 3," before taking a break completely after 2007. It would be another five years before director David O. Russell's lured him out of semi-retirement with a role in his Oscar-nominated film "Silver Linings Playbook."
After "The Boxer" in 1997, Day-Lewis went into semi-retirement in order to pursue his passion for woodworking. He moved to Florence, Italy, and eventually took up shoemaking as an apprentice. Following a five-year break, he returned to acting for Martin Scorsese's "Gangs of New York," earning an Oscar nomination for Best Actor.
In September 2009, the English singer announced that she was considering a career in acting, that she would not renew her record contract, and that she had "no plans" to make another record. She opened a clothing store with her sister, launched her own record label and started a family (giving birth to daughters in November 2011 and January 2013). She started recording music again in 2012 and tweeted in August 2013 that new music would be coming "soon."
After initially indicating he planned to retire in the fall of 2012, the former four-time heavyweight boxing champion decided not to go through with his formal announcement, planned for his 50th birthday party on Oct. 20, 2012. Later that month he told TMZ that he definitely wasn't retiring, saying that he still considers himself a "serious contender."
After announcing he was retiring from stand-up comedy on Dec. 3, 2012, Williams reversed course just three days later, with a representative telling TMZ that his sudden retirement announcement was due to him feeling "unappreciated" and "totally disrespected by all the things that happen to him in the city of Seattle." A day before his "retirement" announcement, Williams had been arrested after a bar dispute in Seattle.
In February 2013, Braxton said she was retiring from music and would like to focus on acting. However, by June, she had announced that she was back in the studio working on her eighth album, a collaboration with Babyface.
After months of speculation about his future, Pettitte announced his retirement from the New York Yankees in February 2011. This first retirement lasted only one year, with Pettitte sitting out the 2011 season. When he joined the Yankees as a guest instructor during spring training in 2012, he got the itch to return. After two seasons back, he again retired following the 2013 season.
Nearly a full decade after leaving the court in 1983 at the age of 26, 11-time Grand Slam winner Borg returned to tennis in 1991. Growing his hair out like in his heyday and playing with an old-fashioned wooden racket, he failed to win a single set in his first nine matches back, eventually re-retiring in 1993 without having won a single match in his comeback bid.