He was most noted for his blazing fastball and his longevity, routinely throwing pitches exceeding 100 mph, even into his 40s. The media tagged him "The Ryan Express", referencing a 1965 action-adventure film called Von Ryan's Express.

He is considered by many to have been the hardest-throwing pitcher of all time; only Smokey Joe Wood, Walter Johnson, Satchel Paige, Bob Feller, Sandy Koufax and possibly Cy Young are thought to have had similar velocity. Ryan was an eight-time MLB All-Star, and his 5,714 career strikeouts ranks first all-time. Given the nature of modern pitching, with starters seldom going beyond 100 pitches (or about six innings), and given the gap between Ryan's record and second place, it is difficult to see how the record could be broken. Ryan also is the all-time leader in no-hitters with seven; at least three more than any other pitcher. He also is tied with Bob Feller for the most one-hitters with 12.

Ryan was born in Refugio, Texas, but his family moved to the Houston suburb of Alvin when he was 6 weeks old. He developed his dazzling fastball as a high school pitcher, which impressed the New York Mets enough to draft him in 1965 and promote him to the major leagues late in 1966. When Ryan was called up in 1966, he was the second-youngest player in the league. He would end his career as the oldest player in Major League Baseball.

However, Ryan struggled for a number of years and even was sent back to the minor leagues because of his inability to find the strike zone. He didn't make the majors for good until the 1968 season, and even then was unable to crack an outstanding Mets pitching staff led by Tom Seaver and Jerry Koosman.

Ryan did, however, give people a taste of what was to come in the 1969 World Series, when he entered Game 3 in relief of a struggling starter and shut down the powerful Baltimore Orioles for nearly three innings. Ryan's work enabled the Mets to hang on to win that game, and they went on to upset the Orioles in five games. A videotape of that game, which has occasionally been shown on ESPN Classic, reveals that Ryan's mechanics, with the trademark high trailing leg kick, already were firmly established at that young age.

Ryan truly blossomed as a pitcher after being traded to the California Angels in 1972 for shortstop Jim Fregosi (who would later manage Ryan in Anaheim). Even though the Angels were a sub-.500 team and remained one for most of his time there, he began winning between 19 and 22 games a season regularly. In 1973, he set his first record when he struck out 383 batters in one season, eclipsing Sandy Koufax's old mark by one. This record was made even more impressive by the fact that he achieved it in the first year of the designated hitter in the American League; if AL pitchers had still been batting, Ryan probably would have topped 400 strikeouts that season.

He threw two no-hitters in 1973, added a third in 1974 and a fourth in 1975, tying another of Koufax' records. He led the league in strikeouts seven times in the 1970s. In 1974 he twice struck out 19 batters, tying a single-game record which wasn't broken until Roger Clemens struck out 20 in a 1986 game. Fans, researchers, historians and even players argue frequently about who was the fastest pitcher of all-time. The most common response is Ryan. His fastball was "officially" clocked by the Guinness Book of World Records at 100.9 miles per hour in a game played on August 20, 1974 vs. the Chicago White Sox. Though popular with fans, Ryan did not win over Angels General Manager Buzzie Bavasi, who dismissed him as a flashy .500 pitcher. (Ryan was 26-27 during the two seasons both were with the Angels). When Bavasi let Ryan leave after a 16-14 record in the 1979 season rather than agree to Ryan's demand to become the first player to be paid $1 million per year, Bavasi remarked he only needed to replace Ryan with two 8-7 pitchers.

Ryan signed a lucrative free-agent contract with the Houston Astros after the 1979 season, in which he became the first player to make $1 million a year. The normally light-hitting Ryan got his Houston years started with a bang in a nationally televised game against the Los Angeles Dodgers on April 12, 1980, in which he hit a 3-run home run off future fellow Hall of Famer Don Sutton. It was the first home run of his career (he only hit one more) and garnered 3 of the 6 RBI's he would get that year. On July 4 of that same season, against the Cincinnati Reds at Riverfront Stadium, he recorded his 3000th career strikeout, the victim being Cesar Geronimo (who had the dubious distinction of also being Bob Gibson's 3000th strikeout victim, in 1974). He got his second taste of postseason play in 1980, but the Astros were stopped one game short of the World Series.

On September 26, 1981, Ryan threw his fifth no-hitter to finally break Koufax's mark, becoming the third pitcher to throw a no-hitter in each league. That season, he won the National League ERA title with a miserly 1.69.

After that, Ryan settled into a long string of good - but not great - seasons, highlighted by his breaking Walter Johnson's all-time strikeout record on April 27, 1983, with his 3,509th whiff.

In 1987, Ryan had one of the most bizarre seasons in baseball history. He was by far the most dominant pitcher in the National League, leading the league in ERA (2.76) and strikeouts (270) at the age of 40. However, he received horrendous offensive support all season and finished 8-16. The poor record most likely cost him the Cy Young Award, an honor for which he contended many times but never won.

Ryan left Houston in a contract dispute after the 1988 season and joined the Texas Rangers, back in the American League. Many observers, keeping in mind the aging Ryan had been pitching home games in the air-conditioned Astrodome, thought he would struggle having to pitch outdoors in the oppressive North Texas heat (as the Rangers play outdoors). Others predicted he would do well as American League batters hadn't faced "The Express" since 1979. With more run support than he had in 1987, Ryan had a number of fine seasons for the Rangers.

In 1989, he won 16 games and led the league with 301 strikeouts. Against the Oakland Athletics on August 22, Ryan struck out Rickey Henderson in the fifth inning to become the first pitcher ever to record 5,000 career strikeouts.

Two years later, at 44, he finished fifth in the league in ERA (2.91) and third in strikeouts (203), to again earn Cy Young Award votes.

In 1990, he threw his sixth no-hitter (on June 11) and earned his 300th win (on July 30, against the Milwaukee Brewers). He pitched his seventh no-hitter on May 1, 1991, striking out Roberto Alomar of the Toronto Blue Jays for the final out. Coincidentally, Ryan's second baseman in his first two no-hitters was Alomar's father, Sandy Sr.

Before the 1993 season, Ryan announced his retirement, effective at the end of that season. His very durable arm finally gave out in Seattle on September 22, 1993, when he tore a tendon, ending his career two starts earlier than planned.

However, on August 4, just before the end, Ryan confirmed his reputation as a strong, competitive Texan in one bizarre moment. He had just hit Robin Ventura of the Chicago White Sox with a slow-moving curveball. The normally unflappable Ventura angrily charged the pitchers mound in order to fight Ryan, who was 20 years his senior. Ryan famously defended himself, perhaps better than any other known pitcher in a similar situation. The 46-year-old Ryan – a rancher in the offseason and highly dedicated to workouts during the season – promptly subdued the 26-year-old Ventura in a headlock with his left arm, pummelling Ventura's head with his right fist seven times before catcher Iván Rodríguez was able to pull Ventura away from Ryan. Videos of the confrontation were played on sports highlight reels that evening throughout the country. While Ventura immediately was ejected, Ryan--who barely moved from his spot on the mound in the fracas--was allowed to remain in the game.

Given that he broke many of Koufax's records previously thought to be untouchable, Ryan frequently is compared to him much in the way that Hank Aaron is to Babe Ruth or Pete Rose to Ted Williams and Ty Cobb. There are many similarities; both Ryan and Koufax started in the majors at a very young age and struggled early in their careers, both were primarily "extreme fastball" pitchers noted for achieving previously unprecedented strikeout totals and multiple no-hitters, and both were very closed and private away from the game (though Koufax moreso than Ryan). It was said of Ryan that he started every game with the intention of striking everyone out. Koufax once admitted he began every game with the intention of throwing a perfect game, and failing that, a shutout. They also were both very conscious of their value and had occasional contract disputes with their owners. An astute businessman, Ryan readily admitted the money was a large part of the reason he played as long as he did. Ryan also would be remembered by many players and fans as a roughneck pitcher who did not take failure lightly. The numerous times he would try to bean a player would be a unique part of his legacy.

But there are many differences too: Koufax pitched left-handed and Ryan right-handed; despite his early troubles, Koufax played his entire career with one team whereas Ryan played for several. Koufax was blessed to play on some championship Dodgers teams, whereas Ryan found himself on mostly mediocre teams. Most importantly, thanks to a strong arm that could handle a lot of work, Ryan had one of the longest careers of any player, whereas Koufax's sterling career was cut short in its prime by arthritis and arm trouble. Nonetheless, both stand out as the premier "power pitchers" of their time, if not all-time.

Ryan ranks first all-time in strikeouts (5,714), fewest hits allowed per nine innings (6.56), first in no-hitters (7), fifth in innings pitched (5386), second in games started (773), seventh in shutouts (61) and tied for 13th in wins (324). He also ranks high on the list for four "negative" records; he ranks first all-time in walks allowed (2,795), in wild pitches (277), and he also ranks third all-time in losses (292). He also is ninth all-time in hit batsmen (158). Since Ryan played more seasons than any other player in baseball history (and since through much of his career, the starting pitcher was expected to complete the entire game), and only one pitcher in history at the end of his career has more strikeouts per nine innings (Randy Johnson, who is still active as of 2006), Ryan's career strikeout mark is considered one of the most invulnerable records in baseball.

Ryan is the only major league player to have his number retired by three teams.[1] The California Angels retired the number 30 on June 16, 1992; the Texas Rangers retired his number 34 on Sept. 15, 1996; and the Houston Astros retired number 34 on Sept. 29, 1996.

Ryan also is the only player in Major League history to strike out a side in nine pitches in BOTH leagues. He did it for the Mets on April 19, 1968, and for the Angels on July 9, 1972.

Ryan was the last player who had played in the 1960s to retire from Major League Baseball, beating out Carlton Fisk by 3 months.

He was elected to the Baseball Hall of Fame in 1999, in his first year of eligibility with 98.79% of the vote.[2] That year, he ranked 41st on The Sporting News' list of the 100 Greatest Baseball Players and was elected to the Major League Baseball All-Century Team. He was inducted into the Texas Rangers Hall of Fame in 2003.

Despite Ryan's longevity and statistics, his legacy has been questioned due to his many losses--for his career, he was only 32 games over .500, and his "average" season saw him post a record of 13-12--to some extent justifying Bavasi's criticisms.[3] By comparison, Koufax was 78 games over .500 in a much shorter career, and Cy Young 195 games over .500. His 292 losses rank him third overall, and first among pitchers who played entirely after 1900. He ranked in the top ten in the league in wins eight times, and in losses eight times. Despite the common belief that Ryan played mostly for bad teams, his teams (disregarding Ryan's own wins and losses) had a .503 winning percentage over his career (.506, if you disregard the 1966 New York Mets for which he pitched three innings and which lost 95 games).[1][2] Thus, his winning percentage was only, at best, .023 better than the teams he played on (Walter Johnson, by comparison, was better by .107 than the teams he played on) He had little success in leading teams to the postseason, making it there only five times, and only once to the World Series--as a rookie with the Mets. Despite his spectacular statistics in the area of strikeouts, each counted only as one out, and his no-hitters each counted as only one win.

Ryan's current business interests include ownership of two minor league teams – the Corpus Christi Hooks, which play in the Class AA Texas League, and the Round Rock Express, a Class AAA team in the Pacific Coast League. Both teams are affiliates of the Houston Astros, for whom Ryan also serves as a Special Assistant to the General Manager.

He threw out the first pitch of Game 3 of the 2005 World Series, the first World Series game ever played in Texas, and ultimately the longest in terms of time. The wags at ESPN suggested the Astros might have needed to pull Nolan out of retirement if the game went much longer.

Ryan has co-written six books: autobiographies Miracle Man (with Jerry Jenkins, 1992), Throwing Heat (with Harvey Frommer, 1998) and The Road to Cooperstown (with Mickey Herskowitz and T.R. Sullivan, 1999); Kings of the Hill (with Mickey Herskowitz, 1992), about contemporary pitchers; and instructional books Pitching and Hitting (with Joe Torre and Joel Cohen, 1977), and Nolan Ryan's Pitcher's Bible (with Tom House, 1991).

In addition to his baseball activities, Ryan is majority owner and chairman of Express Bank of Texas and owns a restaurant in Three Rivers, Texas. He served on the Texas Parks and Wildlife Commission from 1995 to 2001. He also appeared in TV ads for Advil for a number of years, a pain medication he recommended for his own arm. He also has appeared in various television commercials shown in the Texas market.