Shani joined the Evanston Speedskating Club at age six and within two months started competing locally. By age 8 he was winning regional age-group competitions and began to hear about the Olympic ideal from his competitors and friends at the Northbrook Speedskating Club. Shani won five National Age Group Championships (1995, 1997, 1999, 2000, and 2003) and also won a North American Championship in 1999. Shani became the first Black speed skater to earn a spot on the U.S. Olympic Team in 2002.  He began making skating history at age 17 when he became the first American skater to earn spots on both the short track and long track Junior World Team, accomplishing that feat three years in a row in 2000, 2001 and 2002. 

At 22, Shani won his third consecutive U.S. All-Around Championship and Regional Qualifier and became the first U.S. skater to make all three World Teams in the same season (World Sprint, World All-Around and World Short Track), winning medals at all three events and ultimately winning the 2005 World Allround Championships in Moscow, Russia.  

At 23, Shani won Gold and Silver at the 2006 Olympics in Torino, Italy, and also repeated his World All-Around Title in Calgary. In the 2007 season, Shani won world titles in the 1000 meter and 1500 meter events.  The following season Shani repeated his 1000 meter World Title. The 2009 season saw Shani win his first World Sprint Title in Moscow, Russia, and his third 1500 meter World Title in Vancouver.  In 2010 he won Gold and Silver in the 2010 Olympic Winter Games - becoming the first speedskater to repeat as Olympic 1000 m Champion - and he won his third consecutive Overall World Cup Titles in the 1000 and 1500 meters.