Morgan played high school football at Easley High School in Easley, South Carolina. In 1972, his team won a state championship. Morgan went on to play college football for the University of Tennessee, where he was an outstanding multi-position player, appearing in all 46 Volunteers games in his four-year career. As a freshman in 1973, he was used primarily as a wide receiver with 22 receptions for 522 yards and 4 touchdowns. In his breakthrough sophomore season, he had 128 rushes for 723 yards and 11 touchdowns, 10 catches for 234 and 2 touchdowns, and 29 punt returns including 1 touchdown, for an SEC-leading 84 points. He made the All-SEC team in 1974 as a wide receiver and a running back. His 1,587 all-purpose yards that year remained a school record until 1987. His junior year, Morgan was used as a running back and also a kick returner. In a game against Maryland he scored 3 touchdowns, including a 50-yard run and 70 yard punt return. He also became the first Volunteer to rush for 200 yards in a game with 201 against Hawaii. His senior year, he balanced his time more, finishing second on the team in both rushing and receiving. He had 201 yards receiving against TCU, the second most at the time. His 11 touchdowns that season placed Morgan second in the SEC to LSU's Terry Robiskie, and earned him 1976 All-SEC honors as a running back and receiver. He holds the all-purpose yards record for the University of Tennessee, which stands at 4,642, and led Tennessee in that category all four seasons. He shares the modern record for career touchdowns with 39, his 28 rushing touchdowns is third all-time, and his 1,615 combined return yards is 5th. Morgan was inducted into the University of Tennessee Hall of Fame in 2000.
Professional career
Morgan was selected by the New England Patriots in the first round of the 1977 NFL Draft. Despite being used primarily as a running back after his freshman year, Morgan's exceptional speed helped him transition back to wide receiver. He averaged over 20 yards per reception his first six seasons, with a career-high and franchise-record 24.1 yards per reception in 1978. He led the NFL in yards per reception in 1979, 1980 and 1981, and ended his career with the three best seasons in that category for a Patriots receiver. He also led the league in receiving touchdowns in 1979 with a franchise-record 12. In a 1978 game against the Baltimore Colts, Morgan had five receptions for a franchise-record 170 yards; he broke his own record in 1981 against the Miami Dolphins with five receptions for 182 yards, a mark that stood for 17 years. Stanley topped 1,000 receiving yards a franchise-record three times. His best season as a Patriot was 1986 when he caught 84 passes for a then-franchise-record 1,491 yards and 10 touchdowns, leading the Patriots to the AFC East Title. Morgan appeared in four Pro Bowls and was selected 2nd Team All-Pro in 1980 & 1986. Morgan was a member of the New England Patriots, and caught six passes for 51 yards in Super Bowl XX. After 13 seasons with New England, he was traded to Indianapolis where he played just one season. At the time, he held the franchise record in every receiving category with 534 catches for 10,352 yards and 67 touchdowns. He also has the franchise record with 38 games with 100+ receiving yards, 10,479 yards from scrimmage, and is second to Kevin Faulk with 11,471 all-purpose yards. He finished his career with 557 receptions for 10,716 yards and 72 touchdowns, along with 127 rushing yards and 989 combined return yards. Morgan was inducted into the New England Patriots Hall of Fame on August 27, 2007.