Twellman showed his athletic prowess early, as he totaled 115 goals and 35 assists while at St. Louis University High School, including a school record 47 as a junior. He also batted .450 as a junior on the varsity baseball team, and lettered in four sports including football and basketball. An accomplished baseball player who graduated with a 3.5 grade point average, Taylor turned down offers to turn pro and instead chose to attend Maryland to play soccer and baseball, and study business administration.

Taylor was a finalist for the Hermann Trophy in 1999, given to the top collegiate soccer player in the country, as well as the Missouri Athletic Club Player of the Year Award. Before leaving after his sophomore season, Twellman amassed 73 points and 27 goals, leaving him in the record books 7th in career points and 10th in career goals. He helped lead the University of Maryland to the NCAA Division I Final Four as a freshman.

A member of the U-17 National Team at the 1997 FIFA U-17 World Championship in Egypt, he scored a pair of goals in a 4-0 victory over Austria and was twice selected a Parade Magazine All-American in soccer. He earned 13 caps and scored 6 goals as a member of the U.S. Under-17 National Team. In 1999, Twellman scored four goals to capture the Bronze Ball at the Under-20 World Championship in Nigeria, making him the first U.S. player ever to take a FIFA tournament award.

Twellman then signed on and spent two seasons with 1860 Munich's reserve side in the German Bundesliga, leading the team in goals his first season at age 20, youngest on the team. Eventually, frustrated with the continued lack of playing time despite his hard work and success when given a chance, he declined a two-year option with the German team in 2001 and returned home to play in MLS.

Twellman was the second overall selection in the 2002 MLS SuperDraft, and quickly found his way into the Revs regular season starting lineup after impressing in pre-season Revs scrimmages. He continued to find ways to score goals in MLS, despite increasing defensive awareness and aggressiveness, and has become one of the most prominent USA rising young stars.

Twellman led MLS in scoring in 2002, notching 23 goals to go along with 6 assists for 52 total points, while leading the Revolution to the Eastern Conference Championship and the MLS Cup finals in the Revs most successful season ever. Along the way Taylor was named MLS Player of the Week after leading the Revolution to a 2-0 victory over the Dallas Burn in the inaugural game at the brand new CMGI Field (since renamed Gillette Stadium) on Saturday, May 11th.

Taylor has compiled the highest career points-per-90 minutes average in the history of MLS with 1.94, beating out previous all-time leader Stern John of the Columbus Crew with 1.92.

Taylor recently made his first international appearance for the USA National team in a 2-0 shutout victory over El Salvador, and is expected to compete for a starting spot on the team that will represent the USA at the 2006 World Cup.

Twellman continues the family history of athletic success in a variety of sports. His father Tim played professional soccer for the Minnesota Kicks and the Chicago Sting of the NASL. His mom, Moochie Twellman, played sports in pre-Title IX days and excelled in field hockey and softball. His grandfather Jim played professional baseball for the New York Yankees, the Detroit Tigers and the St. Louis Browns. His uncle Jay is currently a golfer on the PGA Tour. Younger brother Jamie scored 5 goals and had 3 assists in the 2002 season as a sophomore to help Stanford get to the NCAA Title final game vs. UCLA. Younger sister Alexandra is presently a high school senior and is already fielding recruiting letters from Division I soccer coaches.