Four-time Olympic ski jumping champion Matti Nykanen, whose personal life was affected by alcohol problems, has died aged 55.

The International Ski Federation (FIS) said Nykanen, who also won seven World Championship gold medals, died on Sunday. The cause of death was not immediately known.

Nykanen became a hero of sport in Finland. He was 18 when he won his first competition in the Four Hills tournament, yet with boyish looks he seemed even younger.

He won the gold medal in the large hill event at the 1984 Sarajevo Olympics and took all three gold medals four years later in Calgary, winning the normal hill and large hill as well as the team competitions.

“He is a legend of his sport,” International Olympic Committee president Thomas Bach said in a statement. “Our thoughts are with his family and his friends.”

Nykanen retired in 1991 after winning a then-record 46 individual World Cup events.

His success on skis was balanced by a troubled personal life.

He was twice sentenced to prison sentences for violent behaviour, including a stabbing incident in 2004 and an aggravated assault on his wife in 2009. He also began a career as a singer after his retirement.

Several biographies have been written about Nykanen, and Finnish filmmakers produced a movie, Matti: Hell Is For Heroes, that drew record audiences after its release in 2006.

“A legend in so many ways,” a former prime minister of Finland, Alexander Stubb, wrote on Twitter.

“He will always have a special place in the hearts of winter sports fans around the world.”