In the first season with Sampdoria, Mirante was an understudy of Luca Castellazzi. Nevertheless, at the end of the loan in June 2008, the club bought half of the registration rights of Mirante from Juventus for €1.5 million transfer fee. In the second season Mirante was still served as the understudy of Castellazzi; the co-ownership of Mirante between Juventus and Sampdoria was renewed in June 2009.
On 19 July 2009, he went on loan to Parma in exchange for defender Marco Rossi, both on temporary deals. In June 2010, Sampdoria decided not to buy Rossi but sold Mirante to Parma. The Genoa club bought the remaining half of the player registration rights from Juventus for an additional €1.5 million fee and sold the full player registration rights to Parma for €3.6 million, despite also losing another one of its keepers, Castellazzi, to Internazionale on a Bosman transfer, and failing to sign shot-stopper Marco Storari from Milan, who had been on loan at the club. Since arrived in 2009, Mirante was a regular in Parma's first team. He was the starting keeper of the team until the club formally went bankrupted in June 2015.
Mirante was signed by Bologna on a free transfer on 3 July 2015. He was the first choice of the team. On 19 July 2016, Mirante signed a new three-year contract. However, at the start of 2016–17 season he was diagnosed with a heart problem and had to undergo testing which ruled him out indefinitely; on 31 August 2016 the club signed Alfred Gomis on loan from Torino as an emergency replacement. After missing the next two and a half months of the season, he was finally cleared to play in mid November. Mirante made his debut since his injury on 28 November 2016 against Atalanta. He was the captain of Bologna in 2017–18 season, his last season with the club.
Roma
On 22 June 2018, Mirante joined Roma from Bologna for €4 million transfer fee, signing a three-year contract; on the same day both clubs also announced that goalkeeper Łukasz Skorupski had joined Bologna from Roma for €9 million transfer fee, signing a five-year contract. Mirante visited Rome for a medical on 21 June and was presented with his number 83 shirt on the next day.
Regarded as one of the most promising Italian goalkeepers of his generation in his youth, Mirante is an experienced shot-stopper, who is known for his athleticism, reflexes, positioning, and goalkeeping technique, as well as his ability to save penalties; with 11 stops, he has saved the 13th–highest number of penalties in Serie A history. A tall goalkeeper, with a large frame and a slender build, he also stands out for his aerial game and ability on high balls, while he is less effective at rushing off his line and getting to ground quickly to clear the ball away or deal with low balls and shots; as such, he is not particularly suited to playing as a sweeper-keeper. Due to his calm composure in goal and reserved character, his leadership and ability to organise his defence has also come into question at times in the media. In addition to his goalkeeping ability, he is also comfortable with the ball at his feet.
