In the late 1980s, Agdestein combined top-flight chess with a full-time football career, representing his country at both. In the early 1990s, a knee injury cut short his football activities. In 1999, Agdestein returned to winning ways, topping the Cappelle la Grande tournament that year and the Isle of Man tournament in 2003. Agdestein scored two tournament victories in 2013, when he won the Open Sant Martí in Barcelona with 8½ points out of 9 possible, with a rating performance of 2901, and the Oslo Chess International-Håvard Vederhus' Memorial with 7 points out of 9.