Modra was born in the South Australian town of Port Lincoln on 27 March 1972 as the third of four children,[1][2] and became visually impaired due to congenital juvenile optic atrophy.

[3][4] He grew up on a farm in Greenpatch, about 20 kilometres (12 mi) north of Port Lincoln, and attended high school at Immanuel College.

[2] His sister, Tania Modra, piloted Sarnya Parker in tandem cycling at the 2000 Sydney Games, where the pair won two gold medals.

[6] In the second of the three races in the individual sprint semi-final, Modra and Short fell off their bike after its front tyre rolled off the wheel.

In the lead up to the road world championships in September Modra suffered a broken collarbone and fractured hip due to a fall in training.

[citation needed] In December 2011, he collided with a car while cycling to work, breaking two vertebrae in his neck and one in his spine; this accident hampered his preparations for the 2012 London Games.

[22] At the 2016 Montichiari UCI Para-cycling Track World Championships, Modra won gold with pilot David Edwards in the Men's Tandem 4 km Pursuit.

[23] At the 2016 Rio de Janeiro Paralympics, Modra and his pilot David Edwards won the bronze medal in the Men's Road Time Trial B.