As a player, Radostin Stoychev represented CSKA Sofia, Minyor Buhovo (with whom he won the national title) as well as teams from Portugal, Spain, Austria, Serbia and France (Tours VB).

In his debut 2007–08 season, he won the Italian national championship, an achievement comparable to the feats of Julio Velasco and Paulo Roberto de Freitas.

Nevertheless, Stoychev was reinstated as head coach a few days later following a heavily publicized media cross-fire between him, also supported by several of the team's star players, and the Bulgarian Volleyball Federation's Administration, which prompted the personal involvement of Boyko Borisov himself, the then Prime Minister of Bulgaria, in order to resolve the critical situation.

Stoychev succeeded in qualifying the team for the 2012 London Olympics on his second attempt, but subsequently decided to step down due to a conflict of interest with the Bulgarian Volleyball Federation.

Stoychev returned to Italy in the next season, again on the bench of Trentino Volley, winning the Italian Championship and losing the final of the 2015–16 CEV Champions League.