Nieminen first started coaching at the age of 14, as a goalkeeping coach of U13 youth team of a local club
PP-70 in
Tampere. Nieminen also worked as a goalkeeping coach for
Honka youth sectors, recommended by his friend, a fellow coach
Jarkko Tuomisto. In 2012, while coaching in Honka, he also occasionally helped with the first team in
Veikkausliiga and the reserve team
Pallohonka. Simultaneously, he played for
Karjaa-based
BK-46 in third-tier
Kakkonen and coached the club's youth teams. Later in 2012, he started working for Veikkausliiga club
Turun Palloseura (TPS) as a goalkeeping coach and assistant coach, and played for another
Turku-based club
Åbo IFK in Kakkonen.
Estonia In 2013, while coaching TPS in
Kupittaa, Turku, he was noticed by Estonian goalkeeping coach
Mart Poom. A month later, he was invited to a job interview, and in 2014 he started to coach the goalkeepers of the Estonian youth national teams, as a goalkeeping coordinator of
Estonian FA. He was named in the coaching staff of
Mikael Stahre. After Stahre was replaced by
Matías Almeyda in September, Nieminen's role was reduced in the team.
Orlando Pirates In July 2019, Nieminen signed with
South African Premiership giants
Orlando Pirates. After approximately a year-and-a-half with the club, Nieminen announced his departure in late December 2020, partly due to
COVID-19 pandemic. On 6 July 2023, the club announced that they had reached an agreement with
Feyenoord on the fee for his contract, and he will depart the club. In all three seasons Nieminen was in New York, the club ranked in top five in MLS with the least goals allowed in the league. He joined the coaching team of
Arne Slot. At the end of the season in 2024, the club won the national
KNVB Cup and the
Johan Cryuff Shield.
Finland national team On 24 April 2025, Nieminen was appointed the goalkeeping coach of the
Finland national team, while also continuing his work with Feyenoord. ==Personal life==