On 1 July 2017, Ierardi was signed by Serie C side Ravenna on a season-long loan deal.[1] On 10 September he made his Serie C debut for Ravenna as a substitute replacing Riccardo Barzaghi in the 84th minute of a 5–1 home defeat against Triestina.[2] On 22 September, Ierardi played his first match as a starter for Ravenna, a 1–0 home win over Modena, he was replaced after 81 minute.[3] On 1 October he played his first entire match for Ravenna, a 1–0 away win over Fano.[4] Ierardi ended his season-long loan to Ravenna with only 14 appearances.[5]
Loan to Südtirol
On 13 July 2018, Ierardi was loaned to Serie C club Südtirol on a season-long loan deal.[6] On 30 July he made his debut for Südtirol in a 2–1 home win over Albalonga in the first round of Coppa Italia, he played the entire match.[7] On 5 August he played in the second round in a 1–0 away win over Venezia.[8] One week later he played in the third round, a 2–0 away win over Frosinone.[9] On 17 September he made his Serie C debut for Südtirol in a 1–0 home win over Teramo, he played the entire match.[10] On 26 December he was sent-off with a double yellow card in the 79th minute of a 1–1 away draw against Monza.[11] Ierardi ended his loan to Südtirol with 31 appearances.[5]
Südtirol
On 12 July 2019, after the loan, Ierardi joined to Serie C club Südtirol on a free-transfer and he signed a 3-year contract.[12] On 4 August he made his season debut for the club and he also scored his first professional goal in the 74th minute of a 4–1 home win over Città di Fasano in the first round of Coppa Italia, he played the entire match.[13] Three weeks later, on 25 August, he made his league debut with a 2–1 away win over Vis Pesaro, he played the entire match.[14] On 21 September, Ierardi scored his first in Serie C in the 51st minute of a 1–0 away win over Arzignano Valchiampo.[15] On 22 January he scored his second goal for the club in the second minute of a 2–0 home win over Vis Pesaro.[16]
Vicenza
On 18 August 2020, Ierardi joined to newly promoted Serie B club Vicenza on an undisclosed fee and he signed a 3-year contract.[17]
On 31 January 2024, Ierardi was loaned by Serie B club Lecco, with an option to buy.[19]
Catania
On 16 July 2024, Ierardi signed a two-year contract with Catania.[20]
International career
Ierardi rappresented Italy at U-18 and U-19 level. On 14 January 2016, Ierardi made his debut at U-18 level in a 6–0 home win over Belgium U-18, he was replaced by Niccolò Tofanari in the 78th minute. On 13 April 2016 he played his first entire match for Italy U-18, a 2–1 home defeat against France U-18. On 11 August 2016, Ierardi made his debut at U-19 level in a 1–0 home defeat against Croatia U-19, he was replaced by Niccolò Tofanari in the 70th minute.