He had previously played in Major League Baseball (MLB) for the Los Angeles Dodgers and the Uni-President 7-Eleven Lions in CPBL.

When Kuo made his debut in 2005, he became the fourth MLB player from Taiwan (after Chin-Feng Chen, Chin-hui Tsao, and Chien-Ming Wang).

Kuo was signed as a free agent by the Dodgers on June 19, 1999, for a bonus of $1.25 million,[1] but elbow problems prevented him from participating with the team.

After giving up eight earned runs on 15 walks in only 13 innings pitched in April, he was sent down to the Dodgers' AAA affiliate, the Las Vegas 51s.

Back in Las Vegas for most of July, the Dodgers decided to start Kuo rather than have him work out of the bullpen, hoping that the increased innings would give him a chance to improve his control, and that ample rest between appearances would protect his fragile elbow.

Off-season elbow surgery raised doubts about his endurance, so Kuo was made a long-reliever by manager Joe Torre.

Kuo recorded his first career save on August 14 against the Phillies when he pitched two scoreless innings without allowing a hit.

A triceps injury forced him to miss the last 15 games of the regular season, but he recovered in time for the National League Championship series and was activated on October 9.

He did not rejoin the team until July 27 but returned to form and pitched in 35 games for the Dodgers' bullpen, ending with an ERA of 3.00.

Kuo in the first half pitched in middle relief and set a record by giving up 0 hits against 36 consecutive left-handed batters.

The performance earned him a spot in the 2010 Major League Baseball All-Star Game as a replacement for Jason Heyward, thus becoming the first Taiwanese-born player to be so honored.

[6] Following the 2010 campaign, Kuo was throwing with about 50 or 60 percent effort during the off-season without stopping at the behest of the Dodgers medical staff.

[citation needed] As Kuo typically experiences elbow problems during spring training each year, it was suggested that the off-season throwing exercises would help him avoid the disabled list at the start of the season.

He announced his retirement from professional baseball on October 22, 2018, after the Guardians lost to the Uni-President 7-Eleven Lions in the 2018 CPBL playoffs.