[3] Morini made his Serie A debut for Sampdoria in a 2–0 loss against Roma on 2 February 1964, and in 1969, he was transferred to Juventus.

[5][6][7] Morini made his international debut for the Italy national team in a 1–0 home win over Turkey on 25 February 1973,[7] and was a member of the Italian squad that took part in the 1974 FIFA World Cup.

[7] Although he was still part of the Italy national side during the mid-70s, he was notably excluded by Enzo Bearzot from the Italian squad that finished in fourth place at the 1978 FIFA World Cup.

[5][6] Morini was a fast, strong, and tenacious centre-back, with good technique, who was known for his tackling ability, as well as his tight marking of opposing forwards.

He was given the nickname "Morgan the Pirate" as he excelled as a powerful ball-winner; despite his physical style of play, he was also known for his correct behaviour on the pitch, and he rarely committed aggressive challenges.