Sampdoria Born in
Mendrisio,
Ticino, an Italian-speaking canton, Switzerland, Martinelli moved south to
Italy to start his professional career. He left the reserve team of
U.C. Sampdoria in 2012 for
Calcio Portogruaro Summaga. Martinelli returned to Sampdoria in June 2013; he signed a new five-year contract with the Genoese club. On 2 September 2013, he was signed by
Venezia. On 7 July 2014, he was signed by
Modena in a temporary deal, with an option to purchase.
Brescia He left for
Brescia in the same formula on 9 July 2015. On 25 July 2016, the loan was renewed, and in August 2017 Martinelli signed for Brescia on a permanent basis.
Palermo In August 2019, he was signed by
Serie D club
Palermo. As a regular, and also captaining the team in
Mario Santana's absence, he won promotion to Serie C on his debut season with the
Rosanero. On 7 September 2020, Palermo announced Martinelli was forced to retire from active football due to cardiac issues. ==International career==