Early career

Sandro made his professional MMA debut in November 2004. He fought primarily in his native Brazil, amassing an undefeated streak of 12–0 before debuting for the World Victory Road Presents: Sengoku promotion.

King of Pancrase

Sandro made his Pancrase debut at Pancrase Rising 9 against Daiki Hata. He won by unanimous decision.

Sandro next fought Miki Shida at Pancrase: Shining 2. He won by KO.

In his next fight Sandro fought for the vacant King of Pancrase Featherweight Championship against Masaya Takita. He won via unanimous decision.

Sengoku

Sandro participated in World Victory Road's Sengoku Featherweight Championship Tournament, losing by a "must decide" decision in the semi-finals to judo specialist and former UFC veteran Michihiro Omigawa. Scores were 30–30, 30–30, 30–29 Sandro (i.e. majority draw) but the judges with draws selected Omigawa in a "must decide" decision, giving him the "must decide split decision" 2–1.

His challenged Sengoku Featherweight Champion, Masanori Kanehara at World Victory Road Presents: Sengoku 13.^[3] Sandro won via KO 38 seconds into the first round. Kanehara was sent out of the ring in a stretcher. After the fight Sandro was ranked the No. 5 Featherweight in the world by Sherdog.^[4] On a side note, Marlon weighted 166 lbs one week before the fight.

Sandro lost the Sengoku Featherweight Championship to Hatsu Hioki at World Victory Road Presents: Soul of Fight on December 30, 2010, by unanimous decision (49–47, 48–47, 48–47).^[5] Hioki dominated nearly every round of the fight, and Sandro was given a yellow card in the first round. Sandro was nearly submitted several times in the final round by a chicken wing armlock, then by an armbar.

Bellator Fighting Championships

On February 23, it was announced Sandro had signed a multi-fight deal with Bellator Fighting Championships, and will be competing in their Season Four Tournament fights.^[6] Sandro made his debut with the promotion at Bellator 46 against Genair da Silva in his quarterfinal match of the Bellator Fighting Championships: 2011 Summer Series Featherweight Tournament. While a seemingly clear-cut decision win, Sandro won the fight on only two scorecards (via 30–27 and 29–28 scores). A third judge scored the bout 29–28 for da Silva, which resulted in a split decision victory for Sandro.

Sandro faced Nazareno Malegarie in the semifinals at Bellator 47. He dominated Malegarie, and won the fight via unanimous decision.

Sandro fought Pat Curran at Bellator 48 in the finals of the tournament. After controlling the fight with his superior striking, Sandro lost via head kick KO late in the second round.

Sandro rebounded from the first KO loss of his career by submitting fellow Brazilian Rafael Dias in the first round at Bellator 58.

In March 2012, Sandro entered the Bellator Season Six Featherweight Tournament, where he defeated Roberto Vargas by submission in the first round. In the semifinals at Bellator 64, Sandro defeated Alexandre Bezerra via split decision. Sandro faced Daniel Mason-Straus in the tournament finals at Bellator 68. He lost the fight via unanimous decision.

Sandro faced TUF 14 contestant Dustin Neace on November 16, 2012, at Bellator 81. Sandro won the fight via technical submission due to a rear-naked choke in the first round.^[7]

Sandro then participated in the Bellator Season Eight Featherweight Tournament at Bellator 88 on February 7, 2013, he faced Akop Stepanyan in the quarterfinal round. Sandro won the fight via majority decision.^[8] In the semifinal, Sandro faced Magomedrasul Khasbulaev at Bellator 92 and lost via third-round TKO.^[9]

Return To Pancrase

After a five-year absence, the former King of Pancrase Featherweight Champion returns at Pancrase 252: 20th Anniversary. Sandro took on Yojiro Uchimura. The fight went to a draw.^[10]

Next Sandro fought the current King of Pancrase Lightweight Champion in a Featherweight bout in the main event of Pancrase 266, but came up short losing by split decision.

Bellator return

On May 9, 2014, over a year since his last fight in Bellator, Sandro faced Chris Horodecki at Bellator 119 in Ontario, Canada.^[11] He won the fight via unanimous decision.

Following the victory in his Bellator return, he had a mix of wins, losses, and even a draw in the following years. In 2015, Sandro faced Isao Kobayashi in Pancrase 266, where he pulled off a victory in a split decision. Later in the year, he had a match with Soo Chul Kim in Road FC 025, which ended in a unanimous draw. Despite this setback, Sandro bounced back with a win against Wanderson Michel in November 2015 during Shooto Brasil 59: Bahia. The victory was marked by a submission due to Michel's shoulder injury.

In 2016, Sandro experienced a significant loss against Mu Gyeom Choi via unanimous decision at Road FC 029, a fight that was for the ROAD FC Featherweight Championship. Despite this loss, Sandro finished the year on a positive note, defeating Koyomi Matsushima by TKO in Pancrase 283.

Sandro's winning streak continued into 2017, where he beat Diego Arturo Huerto Jauregui with an arm-triangle choke submission in Shooto Brazil 74. After this fight, Sandro's career was put on hold due to legal troubles; he was imprisoned due to domestic violence charges against his then-fiance. This led to a lengthy hiatus from his MMA career.

After serving a six- layoff, Sandro made a remarkable comeback to the ring in April 2023. Despite being 46 years old, he faced Alexandre Castro in Shooto Brazil 117 and won the bout, knocking out Castro with a front kick in the first round. This victory marked a significant moment in Sandro's career, signaling his return to MMA after overcoming personal and legal challenges.^[12]