After a loan spell with Birmingham City during the 2009–10 season, he moved to Dutch club Ajax, before joining the New York Red Bulls in 2011.

[8] Tainio was one of ten Spurs squad members struck down by a virus on the evening of 6 May 2006 before their crucial final game of the season against West Ham.

[11] Tainio won the 2008 League Cup when Tottenham took a 2–1 extra-time win over Chelsea at Wembley Stadium in the final played on 24 February 2008.

[16] Having recovered from a calf injury sustained on international duty,[17] he made his debut for the club on 13 September in a 1–0 home defeat in the Birmingham derby against Aston Villa, in which he produced a good performance in a less-familiar role at right-back.

[19] He made his Ajax debut on 11 September 2010, playing the last five minutes as a substitute for Demy de Zeeuw in a 2–0 victory over Willem II.

[20] After making only five official appearances while with Ajax, Tainio accepted an offer from Major League Soccer side New York Red Bulls.

[22] 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, assisting on Juan Agudelo's game-winning goal.

[23] On 15 November 2012, Tainio, along with teammates Jan Gunnar Solli, Bill Gaudette, and José Angulo were all denied contract extensions, thus ending their tenure at New York.

After signing with New York Red Bulls in 2011, Tainio announced that he might retire at the international level, citing the long-distance flights and time difference between the States and Finland.

[26] After a two-year hiatus, Tainio made his comeback to the international team, immediately after his contract with the Red Bulls expired.

After Tainio ended his playing career, he worked for his former club Tottenham as a scout, before returning to Finland and starting as an assistant coach of Klubi 04, the reserve team of HJK Helsinki.

[27] In his first season as manager, FC Haka overwhelmingly won the Ykkönen title, earning the club promotion to top tier Veikkausliiga.