Shumenov’s mother was a schoolteacher and his father was a chief accountant. Both worked long hours and Shumenov was left with two aunts to look after him. Shumenov nearly died as a baby, after severe complications from consuming spoiled milk while in the care of his aunts. Even though he eventually recovered, the lingering effects of his health scare stuck with him throughout childhood.
Shumenov developed a love for combat sports while watching Bruce Lee films and began practicing numerous martial arts disciplines as he matured.
As a young man Shumenov earned a law degree and clerked for a judge at the same time he was honing his skills as a fighter.
Shumenov represented Kazakhstan in the 2004 Summer Olympics. His results were:Defeated Aleksy Kuziemski (Poland) 34-22
Lost to Ihsan Yildirim Tarhan (Turkey) 19-27
He qualified for the Athens Games by winning the gold medal at the 2004 Asian Amateur Boxing Championships in Puerto Princesa, Philippines. In the final he defeated PR of China's Lei Yuping.
Shumenov moved to the United States and based himself in Las Vegas where he turned professional in March 2007. In his debut in North Carolina, Shumenov defeated Walter Edwards with a knockout in the first round. He followed this up with another two knockout wins within 4 months.
In March 2008, Shumenov returned to Kazakhstan to fight American Donnell Wiggins for the vacant WBC Asian and interim PABA light heavyweight titles. Shumenov quickly dispatched the experienced Wiggins with a second-round knockout and the next month beat former US national Golden Gloves champion Lavell Finger in the first round to add the vacant WBO Asia Pacific title to his WBC Asian and interim PABA titles.
Shumenov's most high-profile fight came in August 2008 when he faced former world champion Montell Griffin in Chimkent, Kazakhstan to defend his regional WBC and WBO titles. Shumenov was taken to the scorecards for the first time in his career but won the fight clearly winning every round on all three judges cards.
Shumenov was targeting a fight with then WBO World Champion Zsolt Erdei.
On 15 August 2009 and only 8 professional bouts on his record Shumenov received a shot at the WBA belt when he took on the Spaniard Gabriel Campillo. The fight took place in Shumenov's home country of Kazakhstan and resulted in the first loss of his career when Campillo was declared the winner by majority decision. A rematch took place on 9 January 2010, with the result being reversed this time and Shumenov declared the winner by what was considered an extremely controversial split decision. With this victory Shumenov became the quickest man ever to win a world title in the light heavyweight division, beating the record of 15 fights set by Jeff Harding in 1989.
Shumenov made the first defense of his title on 23 July 2010 when he won a unanimous decision against the previously undefeated Viacheslav Uzelkov. Shumenov then arranged to have a unification fight with the then WBO champion Jürgen Brähmer, the fight was scheduled to take place in Kazakhstan 8 January 2011. However just days before the fight was due to take place Brähmer left Kazakhstan and returned to Germany, citing illness as his reason for dropping out of the fight. In his place former middleweight world champion William Joppy stepped in at short notice, and was knocked out by Shumenov in the 6th round.
He successfully defended his title in Las Vegas on 29 July 2011 against former Contender star Danny Santiago and again on June 2, 2012 in Las Vegas against Enrique Ornelas.
Shumenov was promoted to WBA Super champion and retained the WBA Super and IBA Light Heavyweight titles against Tomáš Kovács, a boxer from the Slovak Republic, on December 14, 2013.
Shumenov fought Bernard Hopkins in a unification bout on April 19, 2014, losing his WBA (Super) and IBA Light Heavyweight titles.
Shumenov defeated BJ Flores by a unanimous decision for interim WBA Cruiserweight title at the Palms Casino Resort in Las Vegas on 25 July 2015 in a Premier Boxing Champions bout broadcast live on NBCSN. Flores pressed the action throughout the fight, serving as the aggressor much of the night. Shumenov began ramping up his offense in Round 8, throwing combinations and taking advantage of a tiring Flores. With 10 seconds left to go in the fight, Flores landed a punishing right that sent Shumenov careening into the ropes. Flores didn’t have enough time, though, to take advantage of the opportunity to inflict more damage on a suddenly vulnerable Shumenov, resulting in a unanimous decision victory for Shumenov.
In June 2017, Shumenov retired at the age of 33 because of an eye injury.