Oct. 11 (Bloomberg) -- Christopher Reeve, known for his role as ``Superman'' in movies and later as an advocate for spinal cord research after a horse-riding accident left him paralyzed nine years ago, died yesterday of heart failure. He was 52.

Reeve, who went into cardiac arrest Oct. 9 at his Pound Ridge, New York, home, fell into a coma and died at the Northern Westchester Hospital in Mount Kisco, New York, without regaining consciousness, his publicist Wesley Comb said in a statement. Reeve's family was with him, Comb said.

The 6-foot-4-inch actor with striking good looks and athletic physique became famous for his role as the comic book superhero who goes through life as newspaper reporter Clark Kent. He played Superman in four movies, from 1978 through 1987.

Reeve broke his neck in May 1995 after he fell from a horse. Confined to a wheelchair and unable to talk, Reeve became a leading crusader for research into spinal cord injuries. At a press conference last year, Reeve said it was unsettling how politics has stood in the way of medical research in the U.S.

In last week's debate against President George W. Bush, Democratic presidential nominee John Kerry cited Reeve as a supporter of controversial stem-cell research.

In 2002, Reeve helped set up the Christopher & Dana Reeve Paralysis Resource Center in New Jersey to help provide information for paralyzed people and those caring for them.

``I'm heartbroken that he will not have the opportunity to benefit from some of the therapies he pushed so hard for,'' Dr. Wise Young of Rutgers University, a spinal-cord researcher who treated Reeve, said in an interview with Cable News Network. ``He was first and foremost an advocate for hope and a cure for spinal- cord injury.''

``Those of us who knew him well knew what a deep and strong and gifted guy he was,'' Harold Guskin, Reeve's acting coach and friend, said in an interview on Cable News Network today. ``When the accident happened, the world started to know Chris the way I had known him, as this incredible, strong, caring, deep person who wasn't going to give in to anything.''

Born in New York

Christopher Reeve was born Sept. 25, 1952, in New York City, the son of Barbara Johnson, a journalist, and Franklin Reeve, a writer and professor of Slavic languages at Columbia University.

When he was four, Reeve's parents divorced. His mother moved Christopher and his younger brother Benjamin to Princeton, New Jersey, where she later married investment banker Tristam Johnson. The boys attended the exclusive private Princeton Day School.

Reeve often traced his love of acting to his childhood when he and his brother used cardboard boxes as ships and pretended to be pirates.

By age 8, Reeve had appeared in school plays and was taking piano lessons. At age 9, he was picked to be in the Gilbert & Sullivan operetta ``Yeoman of the Guard'' for Princeton's McCarter Theater.

``While I was growing up,'' Reeve said, ``I never once asked myself, `Who am I?' or `What am I doing?' Right from the beginning, the theater was like home to me. It seemed to be what I did best. I never doubted that I belonged in it.''

Attended Juilliard

When he was 15, Reeve got a summer apprenticeship at the Williamstown Theater Festival in Massachusetts. By 16, he had an agent. After graduating from high school, Reeve toured the country as Celeste Holm's leading man in ``The Irregular Verb to Love.'' He entered Cornell University where he majored in English and music theory, and continued to act, performing at the Boothbay (Maine) Playhouse, the Williamstown Theatre and the San Diego Shakespeare Festival.

After graduating from Cornell in 1974, Reeve was one of two students accepted for advanced study at New York's Juilliard School of Performing Arts. Actor Robin Williams was the other, and they became roommates. He studied under actor/director John Houseman.

Reeve then played in the long-running television soap opera ``Love of Life, and in 1976 he made his Broadway debut in ``A Matter of Gravity,'' playing Katharine Hepburn's grandson. He later starred in Lanford Wilson's ``Fifth of July'' as the embittered Kenneth Talley, a gay, crippled Vietnam War vet.

Wins `Superman' Role

In 1976, Reeve got a small part in the submarine adventure movie ``Gray Lady Down.'' He returned to New York City, in the off- Broadway production ``My Life.'' It was then that he auditioned and was chosen over 200 other candidates for the role of Clark Kent in the 1978 movie ``Superman.''

Reeve said he portrayed Superman as ``somebody that, you know, you can invite home for dinner. Someone you could introduce your parents to.''

Though he appeared in movies and plays, he could not escape the fame of playing ``Superman.''

``As far as I'm concerned there is Superman and then there's Christopher Reeve, and I'm not interested in having them merge. What I'm interested in is acting. I wasn't Superman before and I don't plan to be Superman after.''

Most of the first ``Superman'' movie was shot in England, and it was then that Reeve met modeling executive Gae Exton. They had two children, Matthew and Alexandra. Reeve later married Dana Morosini; they had one son, Will.

Riding Accident

Reeve chose his film roles carefully, appearing in small films with directors like Sydney Lumet or James Ivory, whom he greatly respected and worked with in ``The Bostonians'' and ``The Remains of the Day.''

In May 1995, during an equestrian event in Culpeper, Virginia, Reeve's horse balked at a rail jump, throwing him forward. He landed head first, fracturing the uppermost vertebrae in his spine. Reeve was instantly paralyzed from the neck down. Surgery stabilized the shattered C1-C2 vertebrae.

After six months at Kessler Rehabilitation Institute in New Jersey, Reeve returned to his home in Bedford, New York, confined to an electric wheelchair, which he operated by sipping or puffing on a straw. He experienced bouts of pneumonia, infections, blood clots, and other problems during his paralysis.

Reeve still tried to remain active as an actor, and in 1999 he received a Screen Actors Guild Award for his role as Jason Kemp in a television remake of ``Rear Window.'' He also received a Grammy award for his spoken album ``Still Me.''

Goldman Sachs Presentation

In a presentation on Nov. 4, 2003, to Goldman Sachs Group Inc. in New York as part of the firm's disability awareness month, Reeve spoke about his own disability:

``I felt guilt at not only have I ruined my life but I've also ruined my family's life too. I became dependent. That was more devastating than actually hearing the details.

``Sometimes those of us that are committed to big achievements misunderstand what success is. I don't care if you make X billion dollars. It's not going to make you happy if your kids don't want to spend time with you. Please don't neglect the relationships in your life. If you try to fulfill your own dream all by yourself, there are many ways you can come up empty-handed.''

In addition to his wife Dana and son Will, 12, Reeve is survived by his two other children, Matthew, 25, and Alexandra, 21, his parents, and his brother, Benjamin Reeve.