He went to Arizona State University as a four-year starter. Plummer went to high school at Capital High School in Boise. An All-American at Capital, Plummer passed for 6,097 yards and 68 touchdowns, completing 69 percent of his passes. In addition, he also ran for over 600 yards and 10 touchdowns on the ground. Plummer led the Capital Eagles to a state high school football title in 1991, defeating the previously unbeaten Twin Falls Bruins in the championship game.

In 1993, Jake Plummer enrolled at Arizona State, where he became the first true freshman to start at quarterback since 1984. As a starter, he compiled a 15-8 record in Sun Devil Stadium. Plummer is the school's all-time leader in pass completions, passing attempts, and passing yards, and his 65 career touchdown passes in college are ranked third all-time in Pac-10 conference history. One of his most notable games as an ASU player was in 1996 when he led the team to a 19-0 victory of defending national champion Nebraska; he was 20-26 for almost 300 yards in that game. That year he was one of the finalists for the Heisman Trophy. At Arizona State, he became great friends with the late Pat Tillman, who were also teammates on the Arizona Cardinals squad before Tillman decided to go to the Army.

Drafted in the second round of the 1997 NFL Draft by the Arizona Cardinals, Plummer started that season as the third-string QB behind Kent Graham and Stoney Case, but made his first career start in Week 7 of the season against the Philadelphia Eagles. That season, he set rookie records for the Cardinals in passing (159 of 296; 53 percent) with 15 touchdown passes and 15 interceptions. In only his fourth NFL start, he set an NFL rookie record with 388 passing yards against the New York Giants, breaking Troy Aikman's mark of 379 established against the Cardinals in 1989.

The year 1998 was a Pro Bowl-type season for Plummer. Second in the NFC to Green Bay's Brett Favre in passing marks all year, he was named an alternate for the Pro Bowl, partly due to an improbable comeback that he engineered against the Dallas Cowboys on November 15, 1998. With his team down 28-0 at halftime, Plummer passed for 314 yards in the second half (465 total yards) to bring his team back to within 35-28, but ultimately lost the game.

The year 1999 was an injury-plagued season for Plummer. He suffered a sprained thumb in the second preseason game, broke his finger midway through the season and had nagging hip and groin problems as well. These injuries were partly the reason why he had a bad year; 2,111 passing yards, nine touchdown passes and 24 interceptions for a 50.8 passer rating.

In 2000, Plummer continued his passing woes from the 1999 season, having slightly better numbers (2,946 yards, 19 interceptions, 66.0 quarterback rating), and reached 10,000 career passing yards in only his 47th career start.

The year 2001 just happened to be Plummer's best season in the NFL at that point in his career. He was one of two quarterbacks to take every snap for his team (Kerry Collins was the other), and he passed for over 3,000 yards. He had a stretch of 142 consecutive pass attempts without throwing an interception until January 6, 2002, when he threw an interception to rookie Redskin linebacker Antonio Pierce. He led the NFL in fourth-quarter passing yards in 2001.

Plummer's last season with the Cardinals was in 2002. Again, his passing marks were rather mediocre (53.6 passer rating, almost 3,000 yards), but he passed the 15,000 yard passing yards mark for his career against the San Diego Chargers on September 22.

Plummer signed as a free agent with the Denver Broncos in 2003, replacing Brian Griese as the starting quarterback. With the guidance of the Broncos's head coach Mike Shanahan, he had his best season as an NFL quarterback to that point. He finished the season with a career high 91.2 rating. He had the longest run by a Broncos QB on Monday Night Football, 40 yards against the Oakland Raiders. He led them to a wild card playoff berth where they were beaten by the Indianapolis Colts 41-10 at the RCA Dome.

2004 was a roller coaster ride for Plummer. Along with matching or surpassing some of former Broncos QB John Elway's passing records (including the most passing yards and tieing for the most touchdown passes in the season), he also threw for 20 interceptions, and was seen giving an obscene gesture to the fans in one game. He led the Broncos to a second straight wild card playoff berth at Indianapolis against the Colts where they were soundly beaten again 49-24.

In his third year playing for Denver, he threw 227 pass attempts without an interception, causing some to christen him Jake No Mistake[1], or No Mistake Jake rhyming with his older more well known nickname Jake the Snake. The Broncos relied on the running of Mike Anderson and Tatum Bell, which decreased the number of difficult throws Plummer was required to make. Furthermore, even when the running game stalled, he was still able to pass the football efficiently and without costly errors, finishing the season with 18 touchdowns and only 7 interceptions. He was selected as the second alternate for the 2006 Pro Bowl and was placed on the Pro Bowl roster after injuries to quarterback Carson Palmer and first alternate Drew Brees. However, Plummer had an injury to tend to, causing him to miss his first Pro Bowl appearance. He was replaced by Tennessee Titans quarterback Steve McNair.

The Broncos played excellent football in 2005, capturing the AFC West Title with a 13-3 record and earning the second overall seed in their conference. In an important milestone, the Broncos achieved their first playoff victory since the retirement of John Elway, defeating the defending champion New England Patriots 27-13 at Invesco Field. Despite these accomplishments some critics and media predicted that Plummer's transformation was a facade and that he would inevitably revert to his old ways. The Broncos were soundly trounced 34-17 by the visiting Pittsburgh Steelers in the AFC Championship game on January 22, 2006,a game in which Plummer threw two interceptions and fumbled twice, losing both to the Pittsburgh defense.

Up until near the end of the 2004 season, Plummer has always kept his hair short and face shaved. However, he started growing it and although it was very obvious that his appearance had changed, the fans and the local media didn't take serious notice until well into the 2005 season. The shaggy beard, which could clearly be seen protruding from his chinstrap, earned Plummer nicknames like "Mountain Man Jake" and "Grizzly Adams Pummer". It is so heavily discussed by football enthusiasts that they tend to ignore his accomplishments on the field. Plummer himself has started that growing his hair and beard in honor of his best friend, the late Pat Tillman who sported long hair for quite some time. Plummer has shown great support of him. He was under scrutiny by the NFL in 2004 after he refused to take out the number 40 decal (Tillman's number) for several games after all the NFL teams sported decals of his number for one game. Finally, Plummer and the NFL agreed to celebrate the troops and Tillman during halftime of one Broncos' home game. When the Broncos played against the Steelers in the 2005 AFC Championship game, their quarterback Ben Roethlisberger was also sporting slightly longer than normal hair and a scruffy stubble leading to one radio announcer saying that the game was a battle between Grizzly Adams (Plummer) and Sasquatch (Roethlisberger).