Sumners grew up in Edmonds, Washington. There she began figure skating and was there throughout their figure skating career at home. She was trained by Lorraine Borman.
In 1980 Sumners won the Junior World Championships. From 1982 to 1984 she was U.S. champion in figure skating ladies. It only took part twice in the World Championships. In 1982, she finished sixth and in 1983 she was already world champion in Helsinki before Claudia Leistner and Jelena Wodoresowa. Sarajevo 1984 Sumners denied their single Olympics and won the silver medal behind Katarina Witt. After she finished immediately without participating in the World Cup yet their amateur career and moved to the pros, where they ran at ice revues such as Disney on Ice and Stars on Ice to 1999.
After her world championship win Sumners was made an honorary mayor of Edmonds and after the Olympics one designated the " 5th Avenue " in Edmonds in " Rosalynn Sumners Boulevard " to. Sumners awarded their medals in 1984 to a bank in Edmonds, so that they could be exhibited there. When she went to pick up the medals, they were gone. The bank had now changed hands. After twenty years, the medals were found in a locker of the bank, was stored in the non unclaimed property. After the rediscovery of the medals were returned by the State of Washington in 2004, again at Sumners.
On April 25, 2004 Sumners married the IMG Vice President Bob Cain. IMG is the largest sports marketing agency in the world. More than 20 years earlier, in 1983, Bob Cain did not manage to take Rosalynn Sumners in his sports agency under contract.