After graduating from La Jolla High School, Duback attended Yale University, where he played on the men's soccer team in 1982.
In 1986, Duback returned to San Diego to play during the collegiate off season for the Nomads' senior team, which competed at that time in the Western Soccer Alliance (WSA).
In the fall of 1987, he broke his toe training with the Kansas City Comets during the Major Indoor Soccer League preseason.
[3] By the spring of 1990, Duback was out of contention for a spot on the national team and he signed with the Boston Bolts now of the American Professional Soccer League.
The Rowdies signed him to a short-term contract on May 13, 1993, as backup to starter Bill Andracki and second string keeper Brett Philips.
However, with Andracki suspended and Phillips injured, Duback started the first game of the season and posted a shutout.
In 1983, Duback was the starting goalkeep for the U.S. U-20 national team as it qualified for the 1983 FIFA World Youth Championship in Mexico.
He served as a volunteer coach at his children's school, Woodlawn of Davidson, North Carolina, during the 2004–2005 season.
2009 assistant coach for the Women's Professional Soccer League's (WPSL) Boston Aztec.