The club was reestablished in the summer of 2002 as Associazione Calcio Fiforentina and Florentia Viola with shoe and leather entrepreneur Diego Della Valle as new owner. The club was incorporated into Serie C2, the fourth highest level in Italian football. The only player who remained at the club under the new form is Angelo Di Livio, whose dedication to the cause of the club was a further reason to attract the supporters. With the help of Di Livio and the 30-goal striker Christian Rigano, the club was able to win their Serie C2 group with considerable ease, which could normally result in a move up to Serie C1. Because of the absurd Caso Catania (Catania Caso Catania) however the club was not able to participate in Serie C1 and was admitted to Serie B, something that was only possible due to the Italian Football Federation (FIGC)'s decision to end the Catania problem by expanding the amount of clubs that play in Serie B from 20 to 24 and also promoting Fiorentina because of "sports benefits." In the off-season of 2003 the club also bought back the rights for the Fiorentina name and famous jersey design and also rebranded its name in the name of ACF Fiorentina. The club ended the season in the sixth spot and won the playoff over Perugia in order to return to the top of the league football.
In their first year back to Serie A, however, the club was unable to avoid being relegated, but only managed to stay in the league on the final day of the season with a head-to head records in the match against Bologna as well as Parma. The year 2005 was the time Della Valle decided to choose Pantaleo Corvino as the new sports director. He was then which was followed by the appointment of Cesare Prandelli as the head coach for the next season. The club signed several players during the summer transfer window which included Luca Toni and Sebastien Frey. The move was a major one that led to them finishing fourth with 74 points, and an Champions League qualifying round ticket. Toni recorded 31 goals over 38 matches and was becoming the very first footballer to reach the 30 goal mark ever since Antonio Valentin Angelillo in the 1958-59 season for which Toni was given his European Golden Boot. 14 July 2006 the team Fiorentina had to be relegated back into Serie B due to their involvement in the 2006 Serie A match fixing scandal and were given a 12-point penalty. The team was relegated back to Serie A on appeal, however, with a penalty of 19 points for the season 2006-07. Its place in the 2006-07 Champions League place was also taken away. At the start in the campaign, Fiorentina's penalty decreased from 19 to just 15 after an appeal to Italian courts. Despite this punishment however, they were able to get a spot in the UEFA Cup.
In spite of Toni's departure to Bayern Munich, Fiorentina had an excellent beginning to the 2007-08 campaign and was regarded by Italian head coach of the national team Marcello Lippi, along with other as a possible opponent for the Scudetto and even though their performance slowed in the mid-season, the Viola did manage to get into their place in the Champions League. In Europe the club made it to the semi-finals of the UEFA Cup, where they were defeated by Rangers in the penalty shootout. The 2008-09 season continued the good run with a fourth place finish securing Fiorentina's place for the 2010 Champions League playoffs. The club's European campaign was similar to the one they had in their previous one, they were relegated to in the 2007-09 UEFA Cup and were eliminated by Ajax at the final.
In the season of 2009-10, Fiorentina started their domestic campaign with a strong start, but slowly lost momentum and falling to mid-table status in the conclusion in the campaign. In Europe Fiorentina was a surprising dark horse. After they lost their first game away against Lyon and then putting together an incredible comeback, completing five consecutive wins, winning all of their remaining games (including beating Liverpool both at home at home and on the road). The Viola won the group title however they lost out in the final game to Bayern Munich due to the away goals rule. The controversy was because of a erroneous refereeing decision made by Tom Henning Ovrebo, who allowed a clear offside goal in the favour of Bayern in the first game. Bayern ultimately finished the tournament as runners-up running deep until the final. The incident has brought to light the possibility of implementing videos in soccer. In spite of a successful European performance and reaching the semi-finals at the Coppa Italia, Fiorentina failed to reach the finals for Europe.
On 24 September 2009 Andrea Della Valle resigned from the position of chairman of Fiorentina and announced that the duties of Fiorentina were to be transferred temporarily over to Mario Cognini, Fiorentina's vice-president until a permanent post could be found.
In June of 2010 in June of 2010, the Viola said goodbye to director Cesare Prandelli, at the time being the coach with the longest tenure in team's history. He was leaving to become the coach of for the Italian nation's team. Catania coach Sinisa Mihajlovic was appointed to succeed Prandelli. The team spent a lot of the season's first half in the bottom third position, however their performance improved and Fiorentina ended up finishing on the ninth spot. After a 1-0 loss against Chievo in November of 2011, Mihajlovic was fired and was replaced with Delio Rossi. After an unspecified period of improvement however, the Viola were once again fighting for being relegated, leading to the demotion director of Sportsing Pantaleo Korvino in the early months of 2012 following the loss to Juventus. Their fight for survival was sustained through a string of shocking wins at home away, most notably in Roma in Italy and Milan. When they played at home against Novara with a deficit of 0-2 in less than one hour, coach Rossi chose to change midfielder Adem Ljajic at the start of the game. Ljajic was sarcastically applauding his opponent in anger, and Rossi responded by physically assaulting his player. This was an incident which eventually led to his dismissal at the hands of the club. The manager who replaced him, caretaker Vincenzo Guerini, then guided the team out of the relegation zone and to 13th place to close the season with a bang.
In order to revive the club following the poor season in 2012, the Della Valle family invested heavily in the middle of 2012, purchasing 17 new players and hiring Vincenzo Montella as head coach. The team started the season in good form, but they finished the year in a joint third position and ending the 2012-13 season fourth place, good enough for an entry into the 2013-14 Europa League.
The club lost their fan favorite Stevan Jovetic at the end of 2013, when they sold Jovetic the club to English Premier League club Manchester City for a EUR30 million transfer fee. They also transferred Adem Ljajic and Adem Ljajic to Roma and Alessio Cecci to Torino and used the funds to acquire Mario Gomez, Josip Ilicic and Ante Rebic, to name a few. The season was a success. Fiorentina won the Europa League group, moving to round 32 to play Danish team Esbjerg fB, which Fiorentina defeated 4-2 in an aggregate. In the next round of 16 but they lost to Italian opponents Juventus by a score of 2-1 and eliminated Fiorentina from the tournament. In the final stages year, they finished fourth in the league. They were they also finished the season with the title of Coppa Italia runners-up following a loss of three-one to Napoli at the end of their final.
In 2014-15, in the winter transfer window of 2015 the club sold the star player Juan Cuadrado to Chelsea for EUR30 million. However, they could get the loan of Mohamed Salah in exchange, who proved to be a major player during the second half during the course of. The 2014-15 Europa League campaign saw them reach the semi-finals in which they were eliminated by Spanish team Sevilla which would go on to become champions. In the 2014-15 season, domestically, Fiorentina once again finished fourth and qualified to play in the 2015-2016 Europa League. In June 2015 Vincenzo Montella was sacked as manager of the club after they became frustrated with the coach's inability to demonstrate their dedication to the club being replaced Paulo Sousa, who lasted until June 2017 and then the selection of Stefano Pioli. The captain of the club Davide Astori died suddenly at 31 years old in March of 2018. Astori was suffering from a cardiac collapse while staying in the hotel prior to an away match. The club then retracted Astori's number for kit, 13. Fiorentina was a victim of this season's Serie A campaign and ended the season with losing 14 times in a row and finished 16th with just 41 points. This was 3 points clear of the zone of relegation. On the 9th of April, 2019 Pioli quit as manager, and replaced with Montella.