Johannes Erm was born March 26, 1998, in Tartu. He started school in Tallinn Secondary School of Science. In his youth he played
football in the Estonian club
FC Flora. In 2011, he transitioned into
track and field and started training with his trainer at the time Holger Peel. In 2017 he finished high school and went to study
mechanical engineering in
University of Georgia. Where he was coached by
Petros Kyprianou. In 2021 his coach changed to James Thomas. In 2023, after finishing his studies and returning to Estonia, his coach changed back to Holger Peel. He finished eleventh in the decathlon at the delayed
2020 Olympics in
Tokyo, Japan, with a tally of 8,213 points. He finished ninth at the
2022 World Athletics Championships in
Eugene, Oregon, finishing with a tally of 8,227 points in the decathlon. He also placed ninth in the decathlon at the
2023 World Athletics Championships in
Budapest, Hungary, with a personal best score of 8,484 points. He was selected to compete in the heptathlon at the
2024 World Athletics Championships in
Glasgow, Scotland, in March 2024, and finished in third place overall to win the bronze medal with a personal best 6,340 points. Competing in the decathlon he was a gold medalist at the
2024 European Athletics Championships in Rome in June 2024, with a personal best tally of
8,764 points. Whilst competing at the
2024 Summer Olympics in
Paris, he finished in sixth place overall. In March 2025, he competed in the heptathlon at the
2025 European Athletics Indoor Championships in
Apeldoorn, Netherlands, finishing in fourth place with 6,380 points, coming close to a medal, finishing just eight points behind bronze medalist
Till Steinforth of Germany. He followed that by also competing in the heptathlon at the
2025 World Athletics Indoor Championships in
Nanjing, China, later in the same month, and this time came away with a medal as he set an Estonian national record of 6,437 points to win the silver medal behind
Sander Skotheim of Norway, whilst Germany’s Till Steinforth claimed bronze with 6275. He finished second at
Décastar in July 2025. ==International competitions==