Soto made his pro debut at the age of 17 and accumulated a record of 36-5-2, which included a 14 fight undefeated streak, before challenging for his first major title.
On August 20, 2005, Soto won the interim WBC Featherweight title by beating Rocky Juarez, in a fight which he accepted on two weeks notice.
On November 17, 2007, Soto fought reigning WBO Super Featherweight champion Joan Guzmán but lost the bout by unanimous decision.
The Dominican champion dominated the fight based on his speed of hands, reflexes, and superior boxing skills, effectively counter punching the relentless attack of Soto, who showcased tremendous strength, courage and determination.
However, after lengthy consultations with officials at ringside, referee Joe Cortez disqualified Soto for hitting Lorenzo after he was down in what appeared to be a grazing punch.
[2][3][4] Lorenzo, therefore, was not presented the green WBC belt as its champion, since it, though, opted to ignore the official verdict, and declared the title vacant.
On December 20, 2008, Soto captured the vacant WBC Super Featherweight Championship with a 12-round unanimous decision over Francisco Lorenzo in a rematch of their controversial bout.
Soto, relying on his ability to strike the challenger with barrages, made his third successful title defense by outlasting Maywood's Antillon in a close unanimous decision, December 4, 2010.