Malmstén's first recording came out in 1929, and during his career he made the total of 842 recordings. He recorded and composed songs of different styles, including music for films and children. Like many other Finnish songwriters, he also had several pseudonyms, such as Jori-Setä, Jorkka, Kille Kiljunen, Jori Malmsten ja Matti Reima.
Beside his musical career, he also starred in several films, and also directed one, called "Pikku Myyjätär".
His brother Eugen Malmstén, his sister Greta Pitkänen and his daughter Ragni Malmstén were also popular artists.