Morton was named the NL Rookie of the Year in 1970 and posted a career record of 87–92 with 650 strikeouts and a 3.73 ERA in 1648.2 innings.

He grew up in West Tulsa, where he played baseball on the same Webster High School team as future major-leaguer Rich Calmus.

Morton started his pro career as an outfielder in the Atlanta Braves organization and later converted to a pitcher.

Morton's first career start was on April 11, 1969, the fourth game of the Montreal Expos as a franchise.

In 1970, Morton compiled an 18–11 record for the last-place Expos and was the National League Rookie of the Year, chosen over Bernie Carbo, Larry Bowa and César Cedeño.

He ranked in the top 10 in numerous categories such as innings pitched (ninth), games started (sixth), shutouts (fifth), hits allowed (seventh) and batters faced (eighth with 1,074).

He also went 3-for-4 for three RBIs (including a stolen base off Bob Forsch in the sixth inning) in the 6–2 win by the team.

[4] Morton was part of a five-for-one trade that sent him, Ken Henderson, Dave May, Roger Moret, Adrian Devine and $200,000 from the Braves to the Rangers for Jeff Burroughs on December 9, 1976.

Morton finished his career in the minors, pitching for the Rangers, Phillies and Pirates Triple-A teams until 1978.