Nathan Eovaldi was born in Alvin Texas on February 13, 1990. He attended Alvin High School, the same school that graduated Nolan Ryan. In his junior year Nate underwent "Tommy John" surgery to repair the ligament in his right elbow. He returned in 2008 to earn honorable mention on the Texas All-State team, and committed to attend Texas A&M on a scholarship.

The Dodgers selected Nate in the 2008 amateur draft and he decided to forgo college, signing with the Dodgers instead. He made his way through the Dodger farm system, pitching for the Gulf Coast Dodgers in 2008, the Great Lakes Loons of the Class A Midwest League in 2009 and the Inland Empire 66ers of the California Class A League in 2010. He was promoted to the Double AA Chattanooga Lookouts in 2011 and made the All Star team, posting a 2.62 ERA.

Nate was called to the majors by the Dodgers on August 6, 2011 and started against the Arizona Diamondbacks. He made six starts for the Dodgers and was moved to the bullpen and finished with a 3.63 ERA.

In 2012 he started for the Dodgers but was traded to the Miami Marlins on July 25th. He started 12 games and finished with a 4.30 ERA. In 2013 and 2014 he had similar results and was traded to the Yankees on December 19, 2014.

In New York, Nate developed a split-finger fastball and was 8-0 with a 2.93 ERA from mid June to late August. However, he experienced inflammation in his elbow in September, ending his season. He was 14-3 with a 4.20 ERA. In 2016 it was decided that Nate should have another "Tommy John" surgery after making 24 appearances. He was released on November 23rd and signed by Tampa Bay in February.

Nate did not pitch in 2017 and recovered from his surgery. He made his first appearance for the Rays on May 30, 2018. He made 10 appearances that year for Tampa Bay and was traded to the Red Sox on July 25th for pitcher Jalen Beeks.

He made his Red Sox debut on July 29th, pitching seven shutout innings and beating the Twins, 3-0. The Sox needed to get a solid performance out Nate for a pivotal Game #3 of the ALDS against the Yankees. He was absolutely magnificent and totally shut down New York’s offense, in a 16-1 slaughter. It was off to Houston for Game #3 of the ALCS and Nate pitched another gem with the Sox winning 8 to 2.

In the 2018 World Series Game #3 became an instant classic. Picked to start the fourth game, Nate was called into action to start the 11th inning instead. Nate, who had pitched his heart out, was still on the mound and neither team had really even threatened since the 14th. The Dodgers' Max Muncy led off the inning and got a 3-2 cutter, belt-high on the outside corner. Nate was still standing on the mound, looking over his shoulder as Muncy's home run sailed over the left-field wall to give the Dodgers the walk-off 3-2 victory, ending the longest World Series game ever played. Nate threw 97 pitches and allowed just three hits and the one earned run over his six innings. That he felt frustration over the gut-wrenching loss is understandable, but it certainly was not shared by anyone else on the team. His teammates gave him a standing ovation in the clubhouse. Yes, the Red Sox lost, but Nate Eovaldi was the hero, putting up one of the strongest performances in World Series history.

In December 2018, Nate signed a four-year deal with the Sox for $68 million. In 2019, he made four starts before being placed on the DL with bone fragments in his pitching elbow. He had surgery and was expected to be out for four to six weeks. He made four relief appearances in late July, and returned as a starter in August, finishing with a 2-1 record and a 5.99 ERA.

Nate was named the opening day starter when the season started in July, 2020 because of COVID. He was the only Red Sox starting pitcher with a winning record when he beat the Marlins, 5-3 in the series finale on September 17th. He was later named to the American League All Star team and finished the season with an 11-9 record and a 3.75 ERA.

Nate was Boston's Opening Day starter for the second year in a row in 2021, taking the loss as the Red Sox fell to the Orioles, 3–0. He was named to the American League roster for the All Star Game. He finished the season with an 11–9 record, a 3.75 ERA and 195 strikeouts. He gave up the fewest walks per 9 innings of any major league pitcher, at 1.73.

He had a disappointing season, dealing with injuries that twice put him out of comission in 2022. Over 109 1/3 innings he posted a 3.87 ERA and had allowed the second most homers (21) of any season in his career. After tying for the league lead with 32 starts last season, he made only 20 this year.