Known to most only by his first name, Leandros Symeonidis was a star forward (outside-left) of PAOK during the 1950s - early 1960s. He was born in 1937 in Kilkis. His nickname was Black Arrow (Μαύρο Βέλος).
He started playing with PAOK's youth team at the age of 13. Three years later he joined PAOK's third team which consisted primarily of teens. One year later he advanced to PAOK's first team along with Giannelos and Havanidis. His first game for the first team of PAOK was a friendly game against the Army National team (Εθνική Ενόπλων). He scored two goals in that game and PAOK won 4-0. His first official championship game was against Apollon Athens where he scored his first league goal. In 1955-56 he was called to play with the Under 21 National team.
Leandros was capped 6 times by the Greek National Football Team during his career.
After retirement, he continued working with the management team of PAOK and established a Youth Academy at PAOK (the Academy later in 1974 sprung players like Alavantas, Alexandridis, Skounas, Siggas).