Born in Aizawl, Mizoram, Fanai started playing football as a school-team player before joining Mizo club, Bawngkawn, where he played in the local leagues till 2004. In 2005, Fanai joined the Mohun Bagan-SAIL Academy where he stayed till 2007. While with the Mohun Bagan Academy, Fanai was a part of the side that won the Indian zone of the Manchester United Premier Cup before qualifying for the final rounds in Manchester. In 2007, Fanai signed for Pune in which he was a youth player for them from 2007 to 2010.
In 2010, Fanai signed with newly created Pailan Arrows of the I-League. On 3 December 2010 Fanai played in his first professional match in the league against Chirag United which was also the first league match Pailan Arrows history as the club lost 2–1. On 23 October 2011 Fanai scored a goal against Mohun Bagan in a league match at the Salt Lake Stadium in which he found the net in the 8th minute to give his side the lead before losing 3–1.
Mohun Bagan
For the 2012–13 season Fanai signed with Mohun Bagan, the club he spent some of his youth days with. Fanai made his debut for Mohun Bagan in the league on 6 October 2012 against Shillong Lajong on the first match of the season in which he started and played the full 90 minutes as Lajong won the match 2–0.
For the 2013–14 season it was announced that Fanai had signed with new direct-entry side Bengaluru FC. He made his debut for the team on 1 December 2013 in the I-League against Shillong Lajong at the Bangalore Football Stadium. He came on in the 24th minute for Keegan Pereira as Bengaluru FC won the match 2–1.
Aizawl
After leaving Bengaluru FC, Fanai joined I-League 2nd Division side Aizawl. After the side gained promotion to the I-League, it was announced that Fanai would not be re-signed by the club.
During the 2007–08 season, Fanai was called up to the India U19 side but he did not have a passport at the time so he could not play for the side. Fanai's first U19 tournament was the 2010 AFC U-19 qualifiers in Iraq. He also played with the India U23 side during the 2010 Asian Games in which he played in one match.
