Career
Jairu hails from Gyalshing, West Sikkim and was spotted during the “Search for more Bhaichungs” scheme launched by the Government of Sikkim and was inducted into the Sports Hostel in Namchi. Later he moved to the Sports Academy of Sikkim at Gangtok and passed out in 2008 grabbing a contract with Oil and Natural Gas Corporation F.C. After his stint at Oil and Natural Gas Corporation, he moved to Shillong and joined Rangdajied United F.C.
After spending a season there he signed for Mumbai Tigers F.C. with whom he had a fruitful outing, scoring a number of goals for the team in the 2013 I-League 2nd Division. Salgaocar
On 13 January 2014 it was announced that Bikash Jairu has signed for Salgaocar F.C. on loan from Mumbai Tigers F.C. He made his debut in the I-League on 16 February 2014 against Mohun Bagan A.C. (before Christ) at the Tilak Maidan Stadium in which he came on as a substitute for Clifton Dias in the 46th minute and was again replaced by Milagres Gonsalves in the 87th minute with Salgaocar winning the match 1-0.
East Bengal
On 23 June 2015 Jairu, along with Rahul Bheke (who coincidently both played together for Mumbai Tigers in 2013) signed a season long deal with East Bengal.
Football Club Pune City
In July 2015 Jairu was drafted to play for Football Club Pune City in the 2015 Indian Super League.