Drafted by the Montreal Expos in 1991, Rueter broke into the majors in 1993 at twenty-two years old and posted an 8-0 record in 14 starts.

On July 30, 1996, he was traded to the San Francisco Giants along with Tim Scott for Mark Leiter.

In 1998, despite achieving a career high 16 victories, Rueter's ERA rose from the previous season, finishing with a 4.36 in 187+ innings.

In 2000, Rueter was the first pitcher to start a major league game at Pacific Bell Park in San Francisco.

Rueter also pitched shutout ball in relief of Liván Hernández in Game 7 of the 2002 Series, but the Giants failed to score enough runs to come back.

[citation needed] He posted a career .988 fielding percentage with only seven errors in 581 total chances covering 1918 innings.

Some credited the effects of the QuesTec umpiring system to his decline, because Rueter's success came mostly from being able to "paint the corners" of the strike zone and the system effectively took that ability away from him because it encouraged umpires to call a tighter strike zone.

"[8] Rueter resides in Nashville, Illinois, with his wife and two daughters and his home is famous for its "Shed", a large recreational facility filled with games and sports memorabilia.

When the San Francisco Giants made trips to St. Louis during the baseball season, Rueter invited the team to relax at his Shed.