|Date of birth||9 August 1989|
|Place of birth||Montegranaro, Italy|
|Height||1.76 m (5 ft 9 1⁄2 in)|
|Playing position||Second striker|
|2009–2010||→ Lecce (loan)||35||(13)|
|2014||→ Cesena (loan)||1||(0)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 00:02, 28 January 2014 (UTC).
† Appearances (Goals).
Born in Montegranaro, Province of Fermo, Marche, he moved his first footsteps with his hometown club until the age of 14, when he was noted by FIFA agent Silvio Pagliari who proposed him to Sampdoria, which successively chose to sign the player and include him in their Giovanissimi Nazionali (under-15) squad for the 2003–04 season. He was pivotal in the 2007–08 Sampdoria under-19 double (Campionato Primavera and Coppa Italia Primavera).
On January 11, 2009, he made his first team debut in a Serie A home league game as a second-half substitute against Palermo, a 2–0 loss for the Genoese club. Three months later, exactly on April 26, 2009, he made his first start in a 3–3 draw with Cagliari, with Marilungo scoring two goals, the first ones in his senior career.
On August 27, 2009, Marilungo joined Serie B outfit Lecce on a one-year loan spell. On 12 September 2010, he signed a 5-year contract to stay with Sampdoria, but only four months later, he joined Atalanta in a 4½-year deal for €4.7 million. Sampdoria relegated at the end of 2010–11 season, with Atlanta promoted to Serie A at the same time.
- ""E' cominciato tutto cinque anni fa grazie a Pagliari". Marilungo: da Montegranaro allo scudetto Primavera con la Samp" (in Italian). Quelliche.net. 2008-06-11. Retrieved 2009-10-24.
- Paola Balsomini (2009-04-28). "GUIDO MARILUNGO" (in Italian). Tuttosport. Retrieved 2009-10-24.
- "Elogi della stampa nazionale per Fiorillo e Marilungo" (in Italian). Sampdoria News. 2009-02-25. Retrieved 2009-10-24.
- "Il giovane Marilungo illude la Samp ma il Cagliari non molla: è 3–3" (in Italian). La Repubblica. 2009-04-26. Retrieved 2009-10-24.
- "DALLA SAMP ARRIVA IN PRESTITO L'ATTACCANTE MARILUNGO" (in Italian). Lecce Prima. 2009-08-27. Retrieved 2009-10-24.
- "Il d.g. Gasparin: "Carattere e alternative di qualità"". UC Sampdoria (in Italian). 12 September 2010. Retrieved 16 September 2010.
- "GUIDO MARILUNGO È DELL'ATALANTA" [GUIDO MARILUNGO IS AT ATALANTA]. Atalanta BC (in Italian). 12 January 2011. Retrieved 12 January 2011.
- UC Sampdoria SPA bilancio (financial report and accounts) on 31 December 2011 (Italian)
- "Gagliardini e Marilungo in bianconero" (in Italian). AC Cesena. 17 January 2014. Retrieved 13 June 2014.