Sipilä competed in the 1924 and 1928 Summer Olympics, placing fourth in the 10,000 metres and being part of Finland's winning cross-country team in the 1924 Games.

[4] At the 1924 Summer Olympics in Paris Sipilä first placed fourth in the 10,000 m race (behind Ville Ritola, Edvin Wide and Eero Berg)[5] and then took part in the 10.65 km cross-country race, which doubled as an individual and team competition.

[5][6] In the extremely hot and demanding conditions, more than half of the participants failed to finish, including Sipilä and two other members of the Finnish team, Berg and Eino Rastas; Finland only barely got a valid team result, even though its stars Paavo Nurmi and Ritola placed a clear first and second.

[6] Sipilä was in fourth place in the 6.2 km intermediate standings, ahead of eventual individual bronze medalist Earl Johnson of the United States, but had to drop out shortly after that point.

[6] Sipilä's 30,000 m record was broken in 1931 by Argentina's Juan Carlos Zabala, who went on to win the 1932 Olympic marathon.