With the Pacers, Smits originally backed up Steve Stipanovich, but when Stipanovich suffered a terrible injury that ended his career, Smits ended up starting 71 games in his rookie year, averaging 11.7 points and 6.1 rebounds per game and earning All-Rookie First Team honors. Smits continued to average double-digit point totals in every year of his career, but it wasn't until 1993-1994 that Smits really came into his own as a team leader.
Throughout the Pacers' playoff runs in the mid- and late-1990s, Smits was considered the number two player, behind Reggie Miller, on the deeply talented Pacers team. Smits' highest point-per-game average was in 1995–96 when he averaged 18.5 points per game, relatively modest by NBA "superstar" standards, but the Dutchman endeared himself to Pacers fans with outstanding playoff performances, most notably in Game 4 of the 1995 Eastern Conference Finals where he made a buzzer-beating shot to tie the series.
Smits was named to the Eastern Conference All-Star team in 1998, delivering 10 points, 7 rebounds and 4 assists, including a spectacular behind-the-back pass to New Jersey Nets forward Jayson Williams who followed immediately with a slam dunk.
Smits developed nerve damage in his feet from wearing tight shoes as a teenager. Foot problems hobbled Smits for the majority of his career, and he retired at the conclusion of the Pacers' 1999–2000 season, after Indiana was defeated by the Los Angeles Lakers in the NBA Finals 4 games to 2.
After four surgeries to repair nerve damage to his feet, Smits underwent intensive back surgery in November 2009 to correct cracks in one joint that link his vertebrae. Smits has also undergone arthroscopic surgery on his left knee and had bone chips removed from his left ankle.
In his retirement, Smits is devoting his time to collecting and racing vintage motocrossmotorcycles. On November 30, 2011, Smits was featured in Yahoo! Sports, about his formal participation in competitive motorcross racing. In 2008 Smits won the AHRMA Vintage National Premier 500 Intermediate Class riding a BSA 500.