He finished outside of the podium in 1908 and 1924 and won his first two medals in 1912, a silver in two-handed discus throw and a bronze in the two-handed shot put. In those two-handed throwing events the total was counted as a sum of best throws with a right hand and with a left hand. He finished fourth in the conventional discus throw and shot put. After having his career hampered by the First World War, he made a strong return at the 1920 Summer Olympics by winning gold in the discus throw and silver in the shot put.
Niklander, nicknamed "Oitin kanuuna" ("Cannon from Oitti"), became an Olympic athlete through practice in his home yard and by taking part in athletic competitions arranged by the local fire department. He won 44 national titles in various weight throwing events between 1909 and 1924.