He won the road race, covering the 87 kilometres from Athens to Marathon and back in a time of 3:22:31 despite his bicycle breaking down shortly after turning around and him falling during the return trip.

[3] Other sources tell that he finished the race with a bicycle from a spectator.

In the 1906 Intercalated Games, Konstantinidis participated again, this time in the road race and in the 20 kilometres.

He did not finish in the road race, and was eliminated in the second round in the 20 kilometres.

[3] Konstantinidis co-founded the Athens Cycling Association.