In 2001, Ching was drafted by the Los Angeles Galaxy. In February 2003, Brian was acquired by the San Jose Earthquakes. In 2004, he co-led the league (with Eddie Johnson) in goals with 12. Brian was named MLS Comeback Player of the Year and to the league MLS Best XI for his efforts. In four years in MLS, Ching has scored 26 goals and added 12 assists in league play.
Along with the rest of his Earthquakes teammates, Ching moved to Houston for the 2006 season. He scored four goals in Houston's first-ever game April 2 against Colorado, the seventh player in MLS history to score four goals in a single game. At MLS Cup 2006, Ching scored the tying goal in the 114th minute and scored what turned out to be the winning goal in the penalty kick shootout against New England Revolution. He was also named the Cup most valuable player. Ching's impressive September 30, 2006 bicycle kick versus DC United was voted MLS Goal of the year.
Ching earned his first cap with the US national team on May 26, 2003 against Wales. He is the first Hawaiian and the second Chinese-American to play for the national team. Ching scored his first international goal, an equalizer in the 89th minute against Jamaica in a World Cup qualifier in Kingston on August 18, 2004.
On May 2, 2006, Ching was named to the U.S. men's squad for the 2006 FIFA World Cup in Germany.
He scored a goal in a 2-0 US CONCACAF Gold Cup victory over Trinidad and Tobago on June 9, 2007. He drew a penalty in the box of the second half of the Gold Cup Final against Mexico. Landon Donovan converted the penalty, tying the game at one. The USA won 2-1.
Ching was called in to the USA side to face Barbados in the first round of CONCACAF World cup Qualifying for the 2010 World Cup. He then scored two goals in the US team's largest victory ever, 8-0.
On May 11, 2010, Ching was named to the preliminary U.S. men's squad for the 2010 FIFA World Cup in South Africa.