Although a top player, he was used in a strict platoon at first base with Ed Kranepool. Manager Gil Hodges swore by playing the percentages, alternating many of his teams top positions.
Clendenon made his Mets debut on June 17th at Philadelphia, in a 7-3 loss to the Phillies. That day he got his first Mets hit as well. On June 22nd, he drove in a run in his first game at Shea Stadium, it came in the first of a twin bill sweep against the St. Louis Cardinals. On June 29th against his old Pirates team mates, he drove in three runs, helping Tom Seaver to a 7-3 victory.
At the start of July he went on a tear in the first week with ten hits & 11 RBIs, including five straight games of driving in at least one run. He hit his first Mets HR on July 6th, a three run shot in Pittsburgh against his old Pirates team mates. He drove in four runs that day, leading the Mets in a close 8-7 win. He drove in two runs or more in four games that week, as the Mets went on a six game win streak. On August 5th, he hit a three run HR off the Reds Gerry Arrigo, in a 10-1 Nolan Ryan complete game victory.
At the end of August through the first week of September, he hit five HRs driving in nine runs over a seven game stretch. It began on August 26th, as he hit a two run HR in San Diego, in a 8-4 win over the Padres.
On August 30th he hit a top of the tenth inning HR, off the Giants Gaylord Perry, helping the Mets beat the Giants 3-2. By this point the Mets were closing in on the Chicago Cubs five games back of first place.
On that same road trip, at Los Angeles, he hit two HRs off Don Sutton, on September 2nd at Dodger Stadium, leading the Mets to a 5-4 win. The next day he hit a two run HR off the Dodgers; Claude Osteen as well. On September 9th Tom Seaver pitched a five hit, one run victory against Fergie Jenkins & the Chicago Cubs, bringing the Mets within a half game of first place. Clendenon lead the offense, with a two run HR off Jenkins in the third inning.
Mets Clinch NL East: On September 24th, Clendenon hit a three run HR off the Cards; Steve Carlton in the first inning in front of a wild capacity crowd at Shea Stadium.
In the 5th inning, Clendenon added a solo HR off pitcher; Dave Giusti. He drove in four of the six Mets runs, in a 6-0 Gary Gentry shutout, on the night the Mets clinched the NL East title, against the reigning NL champion; St. Louis Cardinals.
Two days later he hit another HR while driving in two more runs, leading the first place Mets to a 5-0 win over the Phillies. Overall for the 1969 Amazing Mets, Clendenon would hit .252 with 51 hits, 12 HRs, five doubles 31 runs scored, 37 RBIs & a .321 on base %, in 72 games (202 at bats. Defensively he posted a .985 fielding % in 82 games.
1969 Post Season: Clendenon saved his best hitting for the 1969 postseason. Amazingly enough, Donn did not play in the NLCS against the Atlanta Braves because of Gil Hodges strict platoon system. Hodges went with the left handed hitting Ed Kranepool against the Braves right handed pitching.
1969 World Series: Clendenon started out the World Series with two hits in the Game #1 loss to the Orioles in Baltimore, a double & a single. In Game #2 he hit a solo HR off Dave McNally, for the Mets first Series run helping them & Jerry Koosman to the 2-1 victory. He did not play in the third game at Shea Stadium, as Kranepool got the start.
In Game #4 at Shea Stadium, he hit a HR leading off the bottom of the 2nd inning off Mike Cueller. That was the only run the Mets scored until the tenth inning, when they won it on J.C. Martins bunt single. Tom Seaver pitched ten innings allowing just one run, earning his only World Series victory.
In the 6th inning of Game #5, the Mets were down 3-0. Manager Gil Hodges argued that Cleon Jones was hit by a pitch showing the umpire shoe polish on the baseball.
After Jones was awarded first base, the Mets rally began. Clendenon blasted a HR off pitcher Dave McNally, once again. This time the HR brought the Mets right back in the game & got the sell out crowd going wild as they began to feel the Miracle was in reach.
The Mets tied the game in the next inning as Al Weis hit a HR, then went ahead on a Ron Swoboda double in the 8th, as well as an Orioles error leading to another run. The Mets won the game & made history for all underdogs winning the World Series.
Donn Clendenon was voted the Series MVP, Setting a record with three HRs in a five game series. Overall he hit .357 with 3 HRs, a double, two walks, and four RBIs.
Looking back, his professional veteran presence on the club, made a huge impression on his team mates;
Tug McGraw said "Don was probably the key to our whole season.”
Wayne Garrett said he was the last ingredient the team needed, & Art Shamsky called him the catalyst.
Bud Harrelson said :"When we got him, we became a different team. We never had a three-run homer type of guy. He was always humble, never cocky. We were still young kids in that era. He was a veteran that came in and made us better. When you threw him into the mix with the rest of us, we became a dangerous force. He was the MVP, a very dangerous player."
Quotes: After winning the 1969 World Series MVP Award, Clendenon's said: "there is no most valuable player on this team - we've got lots of them."
It was just spectacular to see these young kids mold themselves into winning combinations, those kids did not believe they could lose.''
On Opening Day 1970, Clendenon came to bat as a pinch hitter in the top of the 11th inning at Forbes Field in Pittsburgh. He singled driving home Ron Swoboda & Mike Jorgenson for the two winning runs. On April 19th he had a big day, driving in four runs including hitting a three run HR in big 10-2 Mets win over the Phillies at Shea Stadium. In 14 games in the month of April he drove in eleven runs & hit three HRs.
On May 1st he drove in both runs in a 2-0 Mets win in San Diego helping Tom Seaver to get to 5-0. On June 22nd he hit a three run HR in the top of the 8th inning off the Cubs Hank Aguirre leading the Mets to an 8-5 win at Wrigley Field. Later that week he hit another three run HR in Montreal.
Starting July 2nd he drove in at least one run for seven straight games, with a total of nine overall in that week. On July 3rd he came to bat in the top of the 9th inning with two men on in a 2-2 tie in Philadelphia. He singled to left field driving in Ken Boswell & Ken Singleton with what would be the game winning runs. He closed out the series with a 7th inning RBI sac fly to help Jerry Koosman to a 5-4 win.
On July 18th his single in the top of the 9th inning, tied up a game in Los Angles & put the eventual winning run on third base. Cleon Jones drove in that run as the Mets went on to a 4-3 win.
On July 28th he set a Mets record that stood for 38 years, driving in seven runs in a single game. In that game in front of 50,000 fans, against the San Francisco Giants at Shea Stadium, he hit a pair of three run HRs off pitcher Rich Robertson. He also had had a first inning sac fly driving in another run in the Mets 12-2 win.
The next day he hit a two run HR in a Mets losing effort. That July he had 19 RBIs and was batting .320 by the end of the month. As the Mets were in another tight pennant race, Clendenon was the teams main run producer in the months of August & September. In August he had ten multiple RBI games in the month & from August 23rd to the end of the month, he drove in 16 runs.
In a game against Atlanta on August 25th he drove in five runs, gathering three hits along with a two run HR. He went into September with RBIs in five straight games, four multi RBI games.
In September Clendenon had another big month, driving in 22 runs on the month. He drove in runs in 15 of 28 games. On September 23rd he hit a two run HR off former Met; Dick Selma in the top of the 8th inning in Philadelphia, leading to the 5-4 Met win. T
he Mets had a good follow up season to their World Championship but fell short, finishing in third place six games in back of the Pittsburgh Pirates. That season he set a Mets season record for RBIs driving in 97 runs, a record which stood until 1975 when Rusty Staub drove in 105 runs.
Overall in 1970 he hit .288 with 22 HRs 18 doubles 65 runs scored & three triples posting a .348 on base percentage. His seven sac flies were 5th most in the league & he even received votes for the MVP Award.
In 1971 Donn was 35 years old & his production began to drop off. On Opening Day he had two hits & drove in the Mets first run of the season in the 1st inning, leading to a 4-2 win. In his next two games he had three hits in each game then on April 16th he drove in the only run of the game with a solo HR to beat the Pirates at Shea Stadium. On May 16th he hit two HRs in a game against the Atlanta Braves .
On June 19th he hit a walk off HR against Bill Wilson in the 15th inning of a game against the Phillies. On August 28th he had a four RBI day in a 9-2 Mets win, in the first of a twin bill at Shea against the Los Angeles Dodgers. On September 23rd he hit his last career Mets HR, it came off veteran Juan Pizzaro in a 5-4 Nolan Ryan Mets win at Wrigley Field in Chicago.
On the 1971 season the Mets finished third again, 14 games behind the World Champion Pittsburgh Pirates. Clendenon only batted .247 with 11 HRs 10 doubles and 37 RBIs playing in just 88 games.
The Mets had Ed Kranepool having a great year, there was another young first baseman named Mike Jorgenson & a young outfielder/ first baseman slugger named John Milner also waiting in the wings. The 1969 World Series MVP Clendenon was released that October. He played his final season for the St. Louis Cardinals in 1972 but hit just .191 in 136 at-bats.
In his 12-season career, Clendenon played in 1362 games, with 1273 hits, batting .274 with 159 HRs, 192 doubles 57 triples, 574 runs scored, a .328 on base % & 682 RBIs.
In 1200 games at first base he posted a .988 fielding % , turning 1136 double plays while making just 146 errors in 11878 chances.
Retirement: After baseball Clendenon earned a Juris Doctor degree from Duquesne University in 1975. He became a business man, serving five years as CEO of Western International Contractors, and several stints as an attorney with law firms.
In the mid-1980s he was enjoying his wealth but became addicted to cocaine. "I was 49 turning 50; and doing cocaine was kind of like a birthday present for me," he said "I was hooked immediately."
He was arrested for possession in 1988 & forced to resign from the law firm. He sought treatment in Utah, and was diagnosed with leukemia, the same disease that killed his father. He kicked his drug habit and moved away from the big city, "I had to go to a place where I could change my environment, and everything else." He said.
In 1987 he moved to Sioux Falls, South Dakota, a small city that he grew to love. "It is a spiritual community.
People are friendly. It had a low crime rate and has a great school system for my daughter. I can be left alone to pursue my vocation outside of athletics."
Clendenon soon became a certified drug counselor and returned to law in the firm of Clendenon, Henney & Hoy. He also supported numerous local charities and was known for bringing some of his baseball friends to promote events in little Sioux Falls.
Clendenon faced his leukemia bravely, "I will die from it or a side effect of it. It's going to eventually take me, I know. But I keep fighting."
Clendenon's fight ended on September 17, 2005, at age 70. He will live forever in the hearts of Mets fans & go down as a 1969 Amazing Mets World Series MVP & hero.