Nieuwenhuis attended Denver Christian High School in Lakewood, Colorado where he played football, basketball and baseball. As a football player, Nieuwenhuis was an elusive running back who led Denver Christian to a state championship and received scholarship offers from Colorado, Colorado State and Air Force. However, Nieuwenhuis feared that he lacked the size to succeed as a football player at the next level and that he would be converted to a wide receiver and made to redshirt as a freshman. He therefore decided to focus on baseball. As a high school baseball player, Nieuwenhuis was a lightly recruited second baseman and pitcher whose fastball reached 90 miles per hour. Nieuwenhuis played three seasons of baseball at Azusa Pacific University in Azusa, California. There he led the Cougars to back-to-back NAIA World Series appearances in 2007 and 2008 and set school career records in runs scored, with 190, and triples, with 12.
Professional career
New York Mets
Nieuwenhuis was drafted by the New York Mets in the third round of the 2008 Major League Baseball draft out of the Azusa Pacific University. In the minors, Nieuwenhuis primarily was a center fielder, and after hitting.298 in Triple-A Buffalo, Nieuwenhuis was added to the Mets 40 man roster on November 18, 2011. After performing well during his debut with the Mets, Nieuwenhuis garnered the moniker "Captain Kirk" from Mets fans, in reference to the fictional Captain Kirk from the 1960s television series .
2008–2011
Nieuwenhuis began his professional career with the Brooklyn Cyclones in the New York–Penn League, where he played 74 games and hit.277. Nieuwenhuis had 15 doubles, five triples and three home runs among 79 hits in 319 plate appearances. Following his first professional season, Nieuwenhuis continued to play well throughout the Mets' Minor League system. He played at every level, finishing the 2010 campaign at Triple-A Buffalo. In 2011, Nieuwenhuis was shut down with a torn labrum in his non-throwing shoulder. It cost him most of the second half of his season.
2012
Nieuwenhuis was called up by the Mets on April 7, 2012, to replace the injured Andrés Torres. Nieuwenhuis got his first major league hit, an infield single, on the same day he was called up; Nieuwenhuis finished the day 2-4. On April 9, in only his second start and third major league game, Nieuwenhuis hit his first Major League home run against Nationals pitcher Edwin Jackson. On April 27, he hit a walk-off single against the Miami Marlins off of Marlins closer Heath Bell giving the Mets the series sweep against the Marlins. Though he garnered early National League Rookie of the Year consideration for his.297 average, six home runs and superlative outfield defense through June 15, Nieuwenhuis batted.123 with one home run after that date, striking out in more than 44 percent of his plate appearances. By July 28, Nieuwenhuis was batting.252 with 7 home runs and 28 RBIs and on July 30, he was optioned to the Mets Triple-A affiliate, the Buffalo Bisons, to make way for Mike Baxter and Jason Bay who were coming off of the disabled list. On August 6 while with Buffalo, Nieuwenhuis was diagnosed with a partial tear of the plantar fascia in his right foot, which occurred while running down the first-base line just days after being optioned by the Mets. He reported to Port St. Lucie for rehab, then on August 22, he was shut down for the rest of the season to heal his foot. Through 91 games and 282 at bats, Niewenhuis was batting.252 with 7 home runs and 28 RBIs, while playing the outfield for the Mets.
2013–2015
In late April, Nieuwenhuis was demoted to the Triple-A Buffalo Bisons after hitting 2 for 16 for the Mets in April. However, he was called back up to the Mets to take Rick Ankiel's spot on the roster. Nieuwenhuis had been hitting.232 at Triple-A before his promotion. On June 10, 2013, Nieuwenhuis was again called up to the Mets playing center field. Nieuwenhuis played in 61 games with the Mets in 2014. Over 112 at-bats he hit.259 with an.828 OPS and three home runs. Nieuwenhuis was designated for assignment on May 19, 2015.
Nieuwenhuis was traded to the Los Angeles Angels of Anaheim for cash considerations on May 27, 2015. He was designated for assignment on June 10.
Second stint with the New York Mets
Nieuwenhuis was claimed by the New York Mets 17 days after the Mets traded him to the Los Angeles Angels of Anaheim. Nieuwenhuis was sent to the Las Vegas 51s and was later promoted back to the New York Mets on July 6, 2015. On July 12, 2015, he hit three home runs in a game against the Arizona Diamondbacks. He was the first player to accomplish this at Citi Field. He is the tenth player in franchise history to hit three home runs in one game and the first to do so in a Mets' home game. When interviewed after his exceptional game that day, Kirk commented in response to his critics: "there's more to life than baseball". On July 29, Lucas Duda joined Nieuwenhuis as the second Met to accomplish the feat at home. On September 8, 2015, Nieuwenhuis hit a pinch-hit, go-ahead home run offJonathan Papelbon of the Nationals, breaking an eighth inning tie and handing the Mets an 8-7 win, a game in which the Mets had once trailed 7-1. After their third consecutive comeback win the next day, the Mets swept the Nats, moving themselves to 7.0 games ahead in the NL East.
Milwaukee Brewers
On December 23, 2015, Nieuwenhuis was claimed by the Milwaukee Brewers off of waivers. Nieuwenhuis was one of nine players competing to be the Brewers center fielder for the 2016 season. On December 3, 2016, Nieuwenhuis and the Brewers agreed to a one-year, $900,000 contract for the 2017 season. He was designated for assignment on April 21, 2017.
On November 14, 2017, Nieuwenhuis signed a minor league contract with the Seattle Mariners. He was assigned to AAA Tacoma Rainiers for the 2018 season. Nieuwenhuis was released by the organization on August 2, 2018.