In high school, Johnson was a three-year starter for the Faith Christian Academy Eagles in Arvada, Colorado. He was a first-team all-conference pick and honorable mention all-state choice as a senior in 2009, despite missing half of the season due to injury. Pierce went 2-1 with a 1.98 ERA and 45 strikeouts in 25 innings as a senior.

Roy Halladay emerged from Arvada High in 1995, which is an inspiration for Pierce.

In 2009, the Rays chose Pierce in the 15th round, but he chose a baseball scholarship to Missouri State.

During the summers of both 2010 and 2011, Johnson pitched for the Harwich Mariners of the Cape Cod League.

In 2012, he had a 2.53 ERA in 14 starts for Missouri State, recording a single-season school record 119 strikeouts to lead the Missouri Valley Conference. He helped lead the Bears to their first NCAA Regional appearance in nine years.

In 2012, Pierce got drafted by the Cubs (see Transactions below). 

In both 2013 and 2014, the Baseball America Prospect Handbook rated Johnson as the 6th-best prospect in the Cubs' organization. They had Pierce at #9 before 2015 spring camps opened. He was at #12 a year later, early in 2016, though he fell to #19 in the spring of 2017.

Pierce has impressive work ethic and character. He is a real baseball rat whose father once worked as vice president of marketing for the Padres. “Qualcomm Stadium was basically my home,” Johnson said in 2012. “I was always out there watching batting practice.”

Cubs senior vice president of scouting and player development Jason McLeod said in 2013. “He’s a kid we like to say is wired correctly. He works his ass off. He’s here for the right reasons. He’s a great teammate.

 Following struggles on an MLB mound, Johnson found his stride in Japan. In 58 games during the 2019 campaign, the right-hander posted a 1.84 ERA/0.801 WHIP over 58.2 innings. The improvement, Johnson says, was because he went back to his roots as a pitcher.

 "I wanted to just find myself again," Johnson said. "I tried to be so coachable that every time somebody told me to make an adjustment or do something else, I tried to do it and, at that point in time, I lost who I was and what my strengths were. So when I went there, I was like, 'You know what, I'm going to jump in with both feet. I'm going to have the best experience I can and I'm going to pitch the way I want to pitch. If I end my career here, I end my career here, but I'm going to go the way I want to go and I can go to bed at night knowing that I gave it my all.' Honestly, when I did that, I jumped in with both feet. I learned the language, I tried the food. I did everything. It was such an incredible experience that I finally found who I was, on and off the field again. I felt like myself and, with that, came a lot of confidence. I'm just trying to ride that wave still."

That confidence helped push Johnson into a situation where the Padres inked him to a two-year deal. That deal, however, came before the season where COVID-19 put a stop to spring training and would eventually shorten the season to just 60 games.

However, despite the world changing because of the pandemic, Johnson still had a comfort level with his new situation because of his upbringing. His father, Don, was the Padres' vice president of marketing from 1992 to 1998, so Pierce had spent plenty of time around the franchise.

 "This is a place I'm familiar with," Pierce said in 2018 before facing San Diego as a San Francisco pitcher. "I grew up around the game here. This is where I found my love of the game. It's a very special time to be here."

Now Pierce had gone from growing up around the franchise to being an integral part of its success in the game's late innings.

"I think because I got to be at a place where I grew up partly, that helped. But that was an organization that they let me be myself too," Johnson recalled. "Those guys greeted me from day one like I was a part of the team and I had been there for years. That meant a lot to me and I think that helped the transition back to the States."

During his three years with the Padres, Johnson appeared in 102 games, striking out 125 batters in 93.0 innings while recording a combined 3.39 ERA/3.19 FIP/1.290 WHIP. The numbers showed that Johnson had returned to MLB as a different pitcher than when he left.

"I feel like I took that wave of confidence from Japan to to San Diego and really was myself again. I enjoyed showing up to the yard every single day, whether I pitched or not, win or lose. I took the highs and lows so much better than I did prior to that. I just became more of a complete player and Pierce Johnson. I wasn't a shell of who I was. (Kevin Henry - April 15, 2023)

TRANSACTIONS

June 2012: The Cubs chose Pierce in the compensation portion of the first round, out of Missouri State University. Johnson signed for $1.2 million, via scout Stan Zielinski.

Pierce was the first pitcher drafted by the organization under president of baseball operations Theo Epstein. 

Sept 20, 2017: The Giants claimed Johnson off waivers from the Cubs.

December 8, 2018: Johnson signed with the Hanshin Tigers of Nippon Professional Baseball.

Dec. 23, 2019: San Diego signed 28-year-old righthander Pierce Johnson of the Hanshin Tigers to a two-year deal worth $5 million, with a team option for 2022.

2022: The Padres exercised the club option on Johnson for $3 million.

Nov 6, 2022: Johnson chose free agency.

Dec 13, 2022: The Rockies signed free agent Johnson to a one-year deal worth $5 million.

July 24, 2023: The Rockies traded RHP Pierce Johnson to the Braves for RHP Victor Vodnik and RHP Tanner Gordon.

Johnson has late life on his 91-96 mph FASTBALL, a hard three-quarters 81-83 mph hammer CURVEBALL with good depth, that also gets him swings-and-misses. It can be his best pitch, and he has real feel for it. And he has an 86-87 mph CUTTER (that some call a slider). Plus, he has improved the feel for his CHANGEUP that is effective vs. both lefties and righthanded hitters.

Pierce can be a little too reliant on his cutter, a pitch he has great confidence in. 

Since Johnson couldn't stay on the mound as a starter who seemed multiple injury prone, the Cubs put him in the bullpen where he finished up strong and healthy in Triple-A Iowa, striking out 35 (while walking 13) in 22.1 innings. As a reliver, he paired down his repertoire, focusing on his fastball and inconsistent, but above-average slurvy breaking ball while shelving his changeup and cutter. He still struggles to pitch with conviction to his arm-side with his fastball. (Spring 2017)

2020 Season Pitch Usage: 4-seam Fastball 41.8% of the time, his Change less than 1%; and Curve 57.9% of the time. Average velocity: 4-seam 96.4 mph, Change 91, and Curve 84.8 mph.

Pierce is more about power than he is finesse. He has the stuff to miss bats. His pitch-ability is impressive.

Johnson pitches from a high angle, pitching downhill.

He displayed good command in 2014 and 2015. He locates his fastball consistently on either side of the plate. he's willing to come inside with his fastball and knock hitters off the plate. When he is missing, it is to the arm side and up, often due to inconsistencies with his mechanics.

When he throws strikes his pitches have proved hard to square up. (As of the start of the 2016 season, Pierce had allowed only a .226 batting average in his pro career.)

If Johnson puts it all together, he profiles as a No. 2 or No. 3 starter with two plus pitches and potentially above-average control. (But the Cubs moved Pierce to the bullpen in 2016.)

"I am trying to focus on just throwing strikes,” Johnson said, “just kind of being fluid instead of sweating every little detail. I had to remember I’ve got to stick with my strengths.”

And after the 2015 season, in Instructional League, Pierce worked on his command—pitching to spots rather than just throwing strikes. He has the pitches, it is just a matter of command in-game and knowing he can't get away with those mistakes at the big league level.

The Cubs shifted Pierce to the bullpen in 2016, easing his workload going forward. And it may get him to the Show quicker. The toughest part was learning to get ready faster.

“I’ve heard nothing but good stuff out of the bullpen with Johnson,” Cubs skipper Joe Maddon said. “Nothing but good stuff.”

Johnson always has thrown hard with a breaking ball he calls his best pitch. But command problems plagued him once he reached Double-A Tennessee in 2014.

“I think the conviction factor for me was the biggest thing,” said Johnson, 25. “As a starter I wasn’t necessarily timid when I was throwing, but the conviction wasn’t necessarily there for me. So being in the pen, just letting it go as hard as I can and trying to throw my breaking ball—I think I can live off those two (pitches) and mix in a changeup—but I really think that’s what clicked for me.”

About moving to the bullpen, he said it “gives me the freedom to just be myself and just let my pitches do what they can.” (Gordon Wittenmyer - Baseball America - 4/07/2017)

2019 Season: In 58 appearances for Hanshin, Johnson posted a 1.38 ERA, and his peripheral numbers were just as impressive. He fanned 91 hitters in 58 2/3 innings, while surrendering just two homers and 5.2 hits per nine innings.

Johnson always had a good breaking ball, dating back to his time with the Cubs. He really found his fastball in Japan, optimizing the spin.

In September 2020, Johnson was waived and then picked up by the Giants. After a lone year in SF, Johnson elected to become a free agent following the 2018 season. He signed with the Hanshin Tigers of Nippon Professional Baseball for the 2019 campaign . . . and wound up as an All-Star in Japan.

On December 23, 2019, Johnson signed a two-year contract with the Padres. In 2020, Johnson finished with a 3-1 record in 24 games played with 27 strikeouts. In 20 innings pitched, he allowed 15 hits, six earned runs, two homers, and nine walks. (MTPeterson@ZoneTracks  - Nov 23, 2020)

As of the start of the 2021, Pierce had a career record of:  6-3 with a 4.59 ERA, having allowed 7 home runs and 55 hits in 64 innings.

2022 Season: Johnson has been a very successful under-the-radar reliever for the San Diego Padres in recent years. He owns a 3.39 ERA, 3.19 FIP, and 32.2 K% over the past 3 seasons (93 IP) combined.

The 31-year-old was still effective in 2022 but did miss a large chunk in the middle of the season due to forearm tendinitis. Fortunately, he was able to come back and pitch meaningful innings for the Padres down the stretch.

The curveball is Johnson’s bread and butter, he throws the pitch more often than anybody in baseball. It’s thrown at a hard 84-mph, spins at a rate in the 92nd percentile, and possesses above average movement in both directions. The offering has always produced great results for Johnson, which also speaks to the good command he has of the pitch given the frequency he’s throwing it at.

He pairs his breaking ball with an active 95-mph fastball that has above average movement as well. This is a power relief profile that is likely available for a fraction of the price that many of the top arms in the class will go for.  ( Cole Mitchem  Nov 28, 2022)

2009: During Johnson's senior year of high school, he suffered a broken hand on a come-backer.

April 2012: Johnson missed a couple of starts with a forearm strain, an issue that also cropped up in high school and again during the fall of his freshman year.

April 3-21, 2014: Pierce missed the first three weeks of the season while on the D.L. recovering from a hamstring injury.

May 22, 2014: Johnson was on the D.L. with a strained left calf.

March, 2015: Pierce spent much of the season on the D.L. with strained lat muscle in his back.

April 12-21, 2016: Johnson was on the D.L. after he was hit on the pitching arm by a come-backer, missing a couple of starts with a bad bruise.

May 3-June 27, 2016: Pierce was on the D.L. with a lat strain.

April 1-14, 2021: Johnson was on the IL with right adductor groin strain.

June 18-29, 2021: Johnson was on the IL with right triceps inflammation.

April 22-Sept 10, 2022: Johnson was on the IL with right elbow tendinitis.

May 1-18, 2024: Johnson was placed on the IL with elbow inflammation.

Braves manager Brian Snitker said that for now, Johnson's injury will not require an MRI.“It’s just rest more than anything.”