Olson attended Omaha Northwest High School in Omaha, Nebraska, where he was a pitcher and led the Huskies to four straight state titles. His father, Bill Olson, was his high school coach. Olson appeared in Sports Illustrated's "Faces In The Crowd" section for the 07-16-84 Vol 61, No. 3.
In the state championship game of his senior year, Olson threw a no-hitter.
After graduating from High School in 1985, Olson went on to pitch at Auburn University for three seasons.
Olson used to come into save situations blowing people away with his 90-plus fastball and a devastating curveball, known as "Uncle Charlie." He was drafted by the Orioles in the 1st round (4th pick) of the 1988 amateur draft, and was given a $200,000 signing bonus before making his debut late in the season.
In 1989, Olson became the first reliever to win the American League Rookie of the Year Award. Olson also set an American League rookie record with 27 saves, and had a 5-2 mark with a 1.69 ERA and 90 strikeouts in 85 innings.
Selected to the All-Star team in 1990, Olson set a club record of 37 saves during the season and collected 31 and 36 in the next two years. On July 13, 1991, Olson combined with 3 other Baltimore pitchers in a no-hitter against the Oakland Athletics. In August 1993, Olson suffered a torn elbow ligament injury that sidelined him for the rest of the year. He finished with 29 saves and a career low 1.60 ERA, but Baltimore opted not to take a risk with him and signed Lee Smith as their new closer. Olson struggled with a succession of injuries over the next years, playing for seven different teams from 1994-97.
In 1998, Olson enjoyed a fruitful comeback with the expansion Arizona Diamondbacks. He set a franchise record of 30 saves (broken by Byung-hyun Kim in 2002) and was also part of a rare feat. On May 28, with Arizona leading the San Francisco Giants 8-5, Olson began the bottom of the ninth inning by striking out Darryl Hamilton, but the Giants then loaded the bases with two walks and a hit before Stan Javier had an RBI grounder that made it 8-6. After pinch-hitter J. T. Snow walked to load the bases, manager Buck Showalter ordered Olson to intentionally walk Barry Bonds, forcing home a run, and bringing up Brent Mayne, who worked the count full before he lined to right field for the third out. Olson put together one of the strangest saves imaginable, working around six walks in 1.1 innings. He threw 49 pitches (not counting the bases-loaded intentional walk) and only 22 of them were for strikes. Olson's only Major League hit was a home run during his last official at-bat of the 1998 season.
Olson was replaced by new closer Matt Mantei in 1999. He finished his career as a setup man for the Dodgers.
In a 14-year career, Olson compiled 217 saves with a 40-39 record, 588 strikeouts, and a 3.46 ERA in 672 innings pitched.
On March 19, 2008, Olson was elected to the Orioles Hall of Fame. He was inducted during the pre-game ceremony before the Orioles vs Rangers game at Oriole Park at Camden Yards on August 9, 2008. He is currently a scout for the San Diego Padres.
Since early 2016, Olson has served as pitching coach to actress Kylie Bunbury, who plays "Ginny Baker" on the scripted FOX television series Pitch. The series is about Major League Baseball's first female player, Ginny Baker, who is a pitcher for the San Diego Padres. Major League Baseball is a co-producer of the series.