Obara made his professional debut on 9 August 2010, losing via fifth-round technical knockout (TKO) in a six-round bout against Kazuyoshi Kumano at the Korakuen Hall in Tokyo, Japan.
[2] After compiling a record of 7–1 (6 KOs) he defeated Hayato Hokazono via fourth-round knockout (KO), capturing the vacant Japanese light-welterweight title on 8 April 2013 at the Korakuen Hall.
[6] He successfully defended the title twice along with two victories in non-title fights, winning all by stoppage, before making his American debut against Walter Castillo on 7 November 2015 at Miccosukee Resort & Gaming in Miami, Florida.
[10][11] After Castillo eventually refused the rematch,[12] Obara defeated Sin Maneesri with a first-round TKO in a stay-busy fight in April 2016[13] before facing Troyanovsky as the IBF mandatory challenger.
The bout took place on 9 September 2016 at the Soviet Wings Sport Palace in Moscow, Russia, with Troyanovsky's lightly regarded IBO light-welterweight title also on the line.
Obara managed to get back into the ring, only to be met by a sustained attack from the champion, prompting referee Michael Ortega to step in and call off the bout, awarding Troyanovsky a second-round TKO victory.
[15] In his next fight he defeated Narong Bunchan, capturing the vacant WBO Asia Pacific welterweight title by second-round TKO on 10 August 2017 at the Korakuen Hall.
Eventually making it to his feet on unsteady legs, the referee decided to wave off the fight, awarding Lagumbay the WBO Asia Pacific title via second round TKO and handing Obara the third defeat of his career.