Born in Sierra Vista, Arizona, Powell played for Mountain Pointe High School in Phoenix, where she was named a WBCA All-American.

She was the first women's basketball player in the history of what is now the Pac-12 Conference to have achieved multiple triple-double games (that is, 10 totals or more in three different positive statistical categories) during the same season.

In 2009, with several of her teammates hobbled by injuries, Powell averaged 16.7 points per game and was the best free throw shooter in the WNBA with 97.9% of attempts made.

Powell was a member of the USA Women's U18 team which won the gold medal at the FIBA Americas Championship in Mar Del Plata, Argentina.

[8] Powell was named to the USA Women's U19 team which represented the US in the 2001 U19 World's Championship, held in Brno, Czech Republic in July 2001.

[9] In 2003, Powell helped the United States women's national basketball team win a silver medal at the Pan American Games in Santo Domingo, Dominican Republic.

During the 2008–2009 and 2009–2010 WNBA off-season, Powell contributed to Fenerbahçe's victories each year in the Turkish women's basketball league championship.

In 2007–2008 she played for CSKA Moscow in Russia, in 2006–2007 for Perfumerias Halcon Avenida in Spain, in 2005–2006 for Fenerbahçe for the first time, also winning the country's championship, and 2004–2005 Basket Spezia in Italy.