Olejniczak has made many recordings for radio and television stations in Poland, France, Slovakia and Japan. For record labels (Polskie Nagrania ‘Muza’, Wifon, Selene, Tonpress, Camerata, Pony Canyon, Opus 111, CD Accord, Sony Classical, BeArTon), he has recorded works by Jean-Philippe Rameau, Wolfgang Amadeus Mozart, Franz Liszt, Fryderyk Chopin, Franz Schubert, Sergei Prokofiev, Wojciech Kilar, Mikołaj Górecki. His albums have won numerous awards, including five Fryderyk awards from the Polish phonographic industry (two in 1995, one in each of 2002, 2003, and 2004), and the Album of the Year Award in 1995 from the magazine Studio (for Chopin concertos with the Sinfonia Varsovia under Grzegorz Nowak).
He performed in Andrzej Żuławski’s film about Chopin entitled La note bleu as the title character and made a guest appearance on Łukasz Barczyk's Influence, playing Ignacy Jan Paderewski in one scene. He also recorded the soundtrack to Jerzy Antczak’s film Chopin: A Desire for Love and Roman Polanski’s film The Pianist.
Olejniczak has taught classes at the Academy of Music in Kraków, and held master classes in Poland, Canada, Columbia, Japan, China and the United States as well as classes at the Mozart Academy. He has also sat on the juries of both Polish and international piano competitions, including the International Chopin Piano Competition (2015). In recognition of his outstanding musical achievements Olejniczak has received the Officer’s Cross of Polonia Restituta (2000), the Annual Reward of the Ministry of Culture in the music category (2003), the Gloria Artis Gold Medal (2005), and the Honorary Pearl of the Polish Economy in the culture category (2010). He has won seven Fryderyk Music Awards in total.