Schmidt was born September 27, 1949, in Dayton, Ohio. He was accepted to Ohio University in 1967 and became the school's best baseball player, mostly playing shortstop. In 1971 he was drafted in the second round by the Philadelphia Phillies. The draft pick immediately following him was George Brett, another great third baseman whose career would closely parallel Schmidt's.
Rapidly progressing through the minor leagues, Schmidt joined the Phillies in 1972. His first full season, 1973, Schmidt struggled and batted only .196; his season was perhaps the worst rookie season ever posted by an eventual Hall of Famer. He blossomed in 1974, however, leading the National League in home runs and demonstrating astounding prowess with the glove. A patient and powerful hitter, Schmidt was best known for hitting many home runs and drawing many base on balls. For the rest of the 1970s Schmidt excelled at bat and with the glove, winning two more home run titles and a succession of Gold Gloves. He helped the usually awful Phillies win three straight division titles from 1976 to 1978, the team's first postseason appearances in 26 years.
A quiet, focused player, Schmidt demonstrated little emotion on the field and was perceived as being somewhat aloof. His relationship with Phillies fans was sometime tumultuous early in his career, which Schmidt later regretted; it warmed late in his career, however. He had an unusual batting stance, turning his back somewhat to the pitcher and waving his posterior while waiting for the pitch. A very muscular, strong man, Schmidt was one of the best athletes in baseball in his time; teammate Pete Rose once said of him, "To have his body, I'd trade him mine and my wife's and I'd throw in some cash." Unlike most power hitters, Schmidt tended to hit his homers to all fields; he is probably the most accomplished home run hitter in baseball history who had no tendency to pull the ball.
A tremendous fielder, Schmidt had a powerful arm and was especially talented at fielding short grounders barehanded. His 404 assists in 1974 remain a record for third basemen. Schmidt also filled in at shortstop and first base when necessity demanded.
In 1980 Schmidt elevated his game to astonishing heights, leading the league in home runs by a margin of 13 and winning the National League's Most Valuable Player Award in a unanimous vote. The Phillies reached the World Series and, for the first time in team history, won it, defeating the Kansas City Royals, led by none other than George Brett. Schmidt was selected as MVP of the World Series, hitting two homers and driving in seven runs.
In 1981 the Phillies again reached the postseason and Schmidt won his second MVP Award. In 1983, Schmidt led the Phillies back to the World Series, but they were defeated by the Baltimore Orioles. In 1986 Schmidt won his third MVP Award, a record for a third baseman.
Injuries to Schmidt's knees and back caused him to miss much of the 1988 season. After a poor start to the 1989 season, Schmidt chose to retire.
Over his career Schmidt set a vast array of hitting and fielding records. In addition to his MVP Awards, Schmidt won ten Gold Gloves, led the league in home runs eight times, in RBI four times, OPS five times, and walks four times. He was named to twelve All-Star teams and in 1983 was named "Greatest Phillie Ever." Since his retirement his uniform number, 20, has been retired by the team in his honor. Schmidt finished his career with 548 home runs and 1,595 RBI, two of the many Phillies career records he holds.
In 1995, Schmidt was inducted into the National Baseball Hall of Fame. Schmidt opted to pursue a more private lifestyle after his career, rather than becoming a manager or coach. He has written a number of articles on baseball for CBS and regularly participates in charity golf tournaments. He has been a vocal advocate for the reinstatement to baseball of Pete Rose.
In 2002 Schmidt was hired by the Phillies to work for several weeks as a hitting coach, each spring training.
In October of 2003, Schmidt was named the manager of the Clearwater Thrashers. The Thrashers are a Single A team within the Philles's minor league system.