After Seaver spent one season with the Jacksonville Suns in 1966, he then made the team with the New York Mets in 1967.
He was named to the 1967 All-Star Game, and got the save by pitching a scoreless 15th inning.
In his rookie season, Seaver was 16–13 for the last-place Mets, with 18 complete games, 170 strikeouts, and a 2.76 earned run average, all Mets' records to that point.
Seaver was named the 1967 National League Rookie of the Year.

Seaver started for the Mets on Opening Day in 1968.
He won 16 games again during that season, and recorded over 200 strikeouts for the first of nine consecutive seasons, but the Mets moved up only one spot in the standings, to ninth.
In 1969, Seaver won a league-high 25 games and his first National League Cy Young Award.
He also finished runner-up to Willie McCovey for the League's Most Valuable Player Award.

In front of a crowd of over 59,000 at New York's Shea Stadium on July 9, Seaver threw ​8 ¹⁄₃ perfect innings against the division-leading Chicago Cubs.
Rookie backup outfielder Jim Qualls broke up Seaver's bid for a perfect game when he lined a clean single to left field.

In the 1969 National League Championship Series, Seaver outlasted Atlanta's Phil Niekro in the first game a 9–5 victory.
Seaver was also the starter for Game One of the 1969 World Series, but lost a 4–1 decision to the Baltimore Orioles' Mike Cuellar.
Seaver then pitched a 10-inning complete game for a 2–1 win in Game Four.
The "Miracle Mets" won the series.
At year's end, Seaver was presented with the Hickok Belt as the top professional athlete of the year and Sports Illustrated magazine's "Sportsman of the Year" award.

On April 22, 1970, Seaver set a major league record by striking out the final 10 batters of the game in a 2–1 victory over the San Diego Padres at Shea Stadium.
Al Ferrara, who had homered in the second inning for the Padres' run, was the final strikeout victim of the game.
In addition to his 10 consecutive strikeouts, Seaver tied Steve Carlton's major league record, at the time, with 19 strikeouts in a nine-inning game.
The Mets also won the game in which Carlton struck out 19, with Carlton victimized by Ron Swoboda's pair of 2-run homers in a 4–3 Mets' victory in St. Louis on September 15, 1969. (
The record was later eclipsed by 20-strikeout games by Kerry Wood, Randy Johnson, Max Scherzer, and twice by Roger Clemens.)
 By mid-August, Seaver's record stood at 17–6 and he seemed well on his way to a second consecutive 20-victory season.
 But he only won one of his last ten starts, including four on short rest, to finish 18–12.
Nonetheless, Seaver led the National League in both earned run average and strikeouts.

In 1971, Seaver led the league in earned run average (1.76) and strikeouts (289 in 286 innings) while going 20–10.
However, he finished second in the Cy Young balloting to Ferguson Jenkins of the Chicago Cubs, due to Jenkins' league-leading 24 wins, 325 innings pitched, and exceptional control numbers.

Seaver had four more 20-win seasons (20 in 1971, 21 in 1972, 22 in 1975, and 21 in 1977).
He won two more Cy Young Awards (1973 and 1975, both with the Mets).
During his tenure with the Mets, Seaver made 108 starts in which he pitched nine or more innings and allowed one run or less.
His record in those starts was 93–3 with 12 no-decisions.
In seven of the 12 no-decisions, he pitched 10 or more innings.
In the 12 no-decisions, he pitched a total of 117 innings, allowing 56 hits and five earned runs, compiling a 0.38 ERA.

Between 1970 and 1976, Seaver led the National League in strikeouts five times, finishing second in 1972 and third in 1974.
Seaver also won three earned run average titles as a Met.
Two famous quotes about Seaver are attributed to Reggie Jackson: "Blind men come to the park just to hear him pitch."
The second was in the 1973 World series, with the Mets up 3 games to 2, and poised to win their second championship.
Seaver started the game, but did not have his "arm" that day, and lost the game.
Jackson is reported to have said "Seaver pitched with his heart that day."
Seaver
After Seaver spent one season with the Jacksonville Suns in 1966, he then made the team with the New York Mets in 1967. He was named to the 1967 All-Star Game, and got the save by pitching a scoreless 15th inning. In his rookie season, Seaver was 16–13 for the last-place Mets, with 18 complete games, 170 strikeouts, and a 2.76 earned run average, all Mets' records to that point. Seaver was named the 1967 National League Rookie of the Year.
Seaver started for the Mets on Opening Day in 1968. He won 16 games again during that season, and recorded over 200 strikeouts for the first of nine consecutive seasons, but the Mets moved up only one spot in the standings, to ninth. In 1969, Seaver won a league-high 25 games and his first National League Cy Young Award. He also finished runner-up to Willie McCovey for the League's Most Valuable Player Award.
In front of a crowd of over 59,000 at New York's Shea Stadium on July 9, Seaver threw ​8 ¹⁄₃ perfect innings against the division-leading Chicago Cubs. Rookie backup outfielder Jim Qualls broke up Seaver's bid for a perfect game when he lined a clean single to left field.
In the 1969 National League Championship Series, Seaver outlasted Atlanta's Phil Niekro in the first game a 9–5 victory. Seaver was also the starter for Game One of the 1969 World Series, but lost a 4–1 decision to the Baltimore Orioles' Mike Cuellar. Seaver then pitched a 10-inning complete game for a 2–1 win in Game Four. The "Miracle Mets" won the series. At year's end, Seaver was presented with the Hickok Belt as the top professional athlete of the year and Sports Illustrated magazine's "Sportsman of the Year" award.
On April 22, 1970, Seaver set a major league record by striking out the final 10 batters of the game in a 2–1 victory over the San Diego Padres at Shea Stadium. Al Ferrara, who had homered in the second inning for the Padres' run, was the final strikeout victim of the game. In addition to his 10 consecutive strikeouts, Seaver tied Steve Carlton's major league record, at the time, with 19 strikeouts in a nine-inning game. The Mets also won the game in which Carlton struck out 19, with Carlton victimized by Ron Swoboda's pair of 2-run homers in a 4–3 Mets' victory in St. Louis on September 15, 1969. (The record was later eclipsed by 20-strikeout games by Kerry Wood, Randy Johnson, Max Scherzer, and twice by Roger Clemens.)  By mid-August, Seaver's record stood at 17–6 and he seemed well on his way to a second consecutive 20-victory season.  But he only won one of his last ten starts, including four on short rest, to finish 18–12. Nonetheless, Seaver led the National League in both earned run average and strikeouts.
In 1971, Seaver led the league in earned run average (1.76) and strikeouts (289 in 286 innings) while going 20–10. However, he finished second in the Cy Young balloting to Ferguson Jenkins of the Chicago Cubs, due to Jenkins' league-leading 24 wins, 325 innings pitched, and exceptional control numbers.
Seaver had four more 20-win seasons (20 in 1971, 21 in 1972, 22 in 1975, and 21 in 1977). He won two more Cy Young Awards (1973 and 1975, both with the Mets). During his tenure with the Mets, Seaver made 108 starts in which he pitched nine or more innings and allowed one run or less. His record in those starts was 93–3 with 12 no-decisions. In seven of the 12 no-decisions, he pitched 10 or more innings. In the 12 no-decisions, he pitched a total of 117 innings, allowing 56 hits and five earned runs, compiling a 0.38 ERA.
Between 1970 and 1976, Seaver led the National League in strikeouts five times, finishing second in 1972 and third in 1974. Seaver also won three earned run average titles as a Met. Two famous quotes about Seaver are attributed to Reggie Jackson: "Blind men come to the park just to hear him pitch." The second was in the 1973 World series, with the Mets up 3 games to 2, and poised to win their second championship. Seaver started the game, but did not have his "arm" that day, and lost the game. Jackson is reported to have said "Seaver pitched with his heart that day." Seaver
Tom Seaver