Solli made his senior debut for Odd Grenland in the 2000 Tippeligaen season and made five appearances, all as a substitute, in his first season. In total, he played 54 league games for the club over three and a half seasons – and helped Odd reach the 2002 Norwegian Cup Final, where they were beaten 1–0 by Vålerenga. His play with Odd Grenland led to interest from various European clubs including Aston Villa, and AC Milan, with which he had a training stint. Solli joined Rosenborg of Trondheimin the summer of 2003 and made four starts and ten substitute appearances in the second half of that season as the club won a 12th consecutive league title. During his first season with Rosenborg he scored his first-ever league goal against Viking on 23 August 2003, in his fifth full season as a professional footballer. He was also a regular in the ensuing European campaigns for Rosenborg and scored an important first-leg goal against Maccabi Haifa in the UEFA Champions League third qualifying round in August 2004. He also played an integral role in helping Rosenborg win the 2004 and 2006 league title. On 16 March 2007, Solli signed a three-year deal with Brann. The transfer fee was. Solli's first season for Brann was a huge success. In partnership with his former Rosenborg colleague Thorstein Helstad, he became an integral part of Brann's title winning squad, and earned a spot on Norway's national squad. During the 2009 season Solli's play with Brann once again led to him receiving interest from other European sides which included German Bundesliga side 1. FC Köln.
United States
Solli signed with Major League Soccer club New York Red Bulls on 24 January 2011. He made his official debut for New York on 19 March 2011, in the Red Bulls' 2011 MLS season opener, a 1–0 victory over Seattle Sounders FC. Solli made 33 official appearances in his first season for New York, playing primarily at right back. In his second season with the club, he scored his first goal for New York on 25 June 2012 in a 3-2 win over D.C. United. On 15 November 2012 New York announced that it would not offer Solli a contract extension, thus ending his tenure with the club.
Return to Europe
Solli signed with Vålerenga of Norway in February 2013. In March 2014 he signed with Swedish side Hammarby.
International
Solli made his debut for Norway in a friendly game against Scotland on 20 August 2003 and scored his only international goal in a 3–2 win against Russia on 28 April 2004. He was capped 40 times. Solli also represented Norway at Under-18 and U-21 level.
Club statistics
Honours
Norway
Norwegian Premier League: 2003, 2004, 2006 and 2007