Smit began his baseball career pitching for PSV[nl] in Eindhoven.[1] The Minnesota Twins signed Smit as an international free agent on 14 July 2002 for $800,000, at the time a record for a player in the top Dutch league.[2][3] While originally a starting pitcher, he worked in relief exclusively in 2005, when he was named as an Appalachian League All-Star. He was added to the Twins 40-man roster after the 2006 season, though he struggled with consistency and conditioning.[4] He was claimed off waivers by the Cincinnati Reds on 12 July 2007. He also dealt with back injuries in 2007 and 2009.[5] He pitched in the American minor leagues through 2010, reaching Double-A.[6] That June, he told the Reds that he wanted to return to the Netherlands.[7][3]
Smit played for the Netherlands in international tournaments. He won the Roel de Mon Award, given to the best youth pitcher, 2000, 2001, and 2002.[8] He also played on the national youth team[2] before debuting with the national team in 2002.[1] He was on the Netherlands teams at the 2004 Summer Olympics in Athens, Greece, where he and his team finished in sixth place, at the 2008 Summer Olympics in Beijing.[9][10] He did not fare well in the Olympics, allowing 8 runs off three home runs in 7 innings in 2004,[11] then going 0–2 with 10 runs allowed in 10+2⁄3 innings in 2008.[12]