In 1985, The Sporting News named Clark an All-American and he later won the Golden Spikes Award from USA Baseball as the best amateur baseball player in the country. A teammate of Rafael Palmeiro, the two were known as "Thunder and Lightning."[9] Clark and Palmeiro were known to dislike each other, dating back to their time at Mississippi State.[10]
In his first major league at-bat on April 8, 1986, on his first swing, Clark hit a home run off Nolan Ryan.[11] A few days later, Clark also homered in his first home game at Candlestick Park. An elbow injury cost Clark 47 games in his rookie season.[11] Clark finished the year with a .287 batting average and placed fifth in National League Rookie of the Year voting.
In his first full season in 1987, Clark had a .308 batting average. Clark was voted the starting first baseman for the NL All-Star team every season from 1988 through 1992. In 1988, Clark was the first Giants' player to drive in 90 or more runs in consecutive seasons since Bobby Murcer from 1975-1976.
In 1989, Clark batted .333 (losing the batting title to Tony Gwynn on the final day of the season) with 111 runs batted in (RBIs). Clark finished second in the NL Most Valuable Player voting to Giants teammate Kevin Mitchell. In 1989, Clark and the Giants defeated the Chicago Cubs in the National League Championship Series (NLCS). In Game 1, Clark had already hit a solo home run. Prior to a subsequent at-bat, Cubs' catcherRick Wrona went to the mound to discuss with Greg Maddux how to pitch to Clark. From the on-deck circle, Clark watched the conversation and read Greg Maddux's lips saying "fastball high, inside." The first pitch was a fastball high and inside which Clark sent into the street beyond right field for a grand slam. Afterwards, pitchers began to cover their mouths with their gloves when having conversations on the pitcher's mound.[12] (The Chicago Tribune's front page the next day paid tribute to his performance with a headline of "Clark's night on Addison", referring to the street outside Wrigley Field where the home runs landed.[13])
In Game 5 of the series, Clark faced Cubs closerMitch Williams with the score 1–1 in the bottom of the eighth inning. Clark singled to center field to drive in two runs, breaking the tie, eventually sending the Giants to the World Series. Clark's efforts, which included a .650 batting average and two home runs, resulted in him being named NLCS MVP. The Giants went on to face the Oakland Athletics in the 1989 World Series, but were swept. In the only World Series appearance of his career, Clark failed to contribute significantly at the plate, finishing with no runs batted in and a .250 batting average while battling tonsillitis.[14]
Clark had become a very durable player since his rookie year injury, setting a San Francisco record with 320 consecutive games played from September 1987 through August 1989.[11] In January 1990, he signed a four-year, $15 million contract with the Giants, which at the time made him the highest-paid player in the majors.[15] However, a string of injuries reduced his playing time in the early 1990s and diminished his production. Clark drove in just 73 runs in 1992, the lowest total since his rookie year.[6]
Texas Rangers (1994–1998)
The Texas Rangers signed Clark to replace his former Mississippi State teammate, Rafael Palmeiro, at first base. Clark made the American League All-Star team in 1994[6] and finished the season with a .329 batting average, the second-highest of his career. He maintained a high level of offensive production throughout his tenure with Texas, finishing below .300 only in 1996. Injuries limited his playing time to 123, 117 and 110 games from 1995 through 1997, but Clark led the Rangers to American League West Division titles in 1996 and 1998. Clark struggled offensively in both the 1996 and 1998 postseasons, though he put together his most productive regular season in seven years in 1998 (.305, 23 HRs, 41 2Bs, 102 RBIs). Following the 1998 season, the Rangers re-signed Rafael Palmeiro, effectively ending Clark's days with the team.
Baltimore Orioles and St. Louis Cardinals (1999–2000)
Clark signed a two-year deal with the Orioles before the 1999 season, again replacing Palmeiro, who had left Baltimore to return to Texas. Part of the reason Clark chose Baltimore was to be near Johns Hopkins Hospital in Baltimore, since Clark's son, Trey, has autism.[16] Clark spent nearly two years with Baltimore but was plagued by injuries. On June 15, Clark got his 2000th hit versus the Kansas City Royals.
At the MLB trade deadline in 2000, the Orioles traded Clark to the St. Louis Cardinals for José León. He was acquired in part to play in place of the injured Mark McGwire.[17] Clark batted .345 while hitting 12 home runs and driving in 42 runs in 51 games. Clark helped the Cardinals defeat the Atlanta Braves in the NLDS with four runs batted in during the series. In the NLCS, the Cardinals faced the New York Mets. Clark batted .412 in the series but the Mets won the series and the National League pennant. Despite being revitalized during his time with the Cardinals, he decided to retire at the end of the season, largely due to familial obligations.[16] Clark batted .319 during his final season and went 1 for 3 in his final game on October 16, 2000.
Will holds the record for most home runs against Hall of Fame Pitcher Nolan Ryan with 6.[24]
It was announced on August 11, 2019, that the Giants would retire Clark's #22 during the 2020 season.[25] However, due to the COVID-19 pandemic the retirement ceremony was postponed to 2022.[26] Clark's number was ceremoniously retired on July 30, 2022.
Clark is married to his wife, Lisa White Clark, whom he wed in 1994.[41][42] Their son Trey was born in 1996.[43] In 1998, at age two, Trey was diagnosed with autism. Will and Lisa also have a daughter, Ella.[16] Clark is a spokesman for Autism Speaks and Anova.[44] In 1999, Clark's wife Lisa had open heart surgery to address a hole that had been undiagnosed since birth.[43]