The Swedish Davis Cup team with Lundqvist as anchor reached the Inter-Zonal final against Mexico in 1962 and Australia in 1964.

In 1964 he won, among other titles, Italian Open and was ranked number 3 in the world after Roy Emerson and Fred Stolle.

As a tennis player, Jan-Erik was known for his aggressive playing style hitting the ball a long distance in front of the body.

He had a very good first serve, and he could hit surprisingly hard sliced and totally unreachable stop balls.

He had in his strongest form in the beginning of the 1960s with few superiors on clay, defeating players such as Manuel Santana, Nicola Pietrangeli, Fred Stolle, Roy Emerson and Neale Fraser.