Fronimidis was born in 1937 and was goalkeeper of Proodeftiki in the mid-1960s when the "Vyssini" arose as a newly-promoted team to win 4th place in the Alpha Ethniki. He transferred to Olympiakos in 1966 for a good deal of cash plus Panagiotis Barbalias, Takis Spetseris and Antonis Tzanetoulakos who went the other way. In the next two years he won two championships with the red-and-whites (1966, 1967).
He stopped playing in 1967 while he was still in top form.
Fronimidis was capped once by the Greek National Football Team.