He attended Charles D. Owen High School in Black Mountain, North Carolina, and Montreat College, and signed his first pro contract with the Baltimore Orioles in 1975.

Stewart established a new record for most consecutive strikeouts in an MLB debut with seven in the Orioles' 9–3 victory over the Chicago White Sox in the second game of a twi-night doubleheader at Memorial Stadium on September 1, 1978.

[5] In a December 17, 1985 trade that sent Jackie Gutiérrez to the Orioles, Stewart was acquired by the Boston Red Sox in a move to strengthen its bullpen.

[5] Upon hearing reports that Gutiérrez was released by two winter ball teams in the Dominican Republic and Venezuela because of erratic behavior which involved frequent fights,[6] the Orioles attempted to have the transaction restructured or voided, alleging that the Red Sox had prior knowledge of any such issues.

[8] American League president Bobby Brown upheld the deal on March 11, 1986,[9] ruling that it was made in "good faith, with neither club knowingly misrepresenting the facts" and that "the Orioles' request to rescind the trade has been denied.

"[10] Years after his retirement, Stewart blamed Boston's 1986 World Series loss on the team's manager, John McNamara.

[13] In October 2006, he was sentenced to 80 to 105 months in the Buncombe Correctional Center on drug possession charges after accepting a plea bargain as a habitual felon.

[14] An autopsy report released by the Henderson County medical examiner seven months later on October 1 disclosed that the causes of death were hypertension and atherosclerotic cardiovascular disease.