[1] Born in Marietta, Georgia,[2] Brad Johnson attended Charles D. Owen High School in Black Mountain, North Carolina.

From 1987 to 1989, Johnson played on the Florida State Seminoles men's basketball team and started 11 games as a freshman.

[8] As third-string quarterback behind starter Rich Gannon and backup Sean Salisbury, Johnson dressed for only one game as a rookie in 1992 but did not play.

[3] In 1994, Johnson became backup to starter Warren Moon and played his first NFL regular season game in Week 3 (September 18).

However, Minnesota lost 38–21 to the Green Bay Packers in Week 7 (October 22), a game in which Johnson completed 10 of 17 passes for 94 yards and one interception.

[3] In the season opener against the Detroit Lions on September 1, Johnson played in the second half after starter Warren Moon suffered an ankle injury amid 5-for-14 passing.

[10] Johnson started his first game of his career the following week on September 8 and led Minnesota to a 23–17 road win over the Atlanta Falcons.

[10] With a Week 15 (December 15) victory over the Tampa Bay Buccaneers 21–10, Minnesota clinched a playoff berth for the season.

[19] Johnson made his postseason debut in the Vikings' NFC Wild Card game against the defending Super Bowl champion Dallas Cowboys on December 28, 1996.

[3][10] In the Vikings' 21–14 win over the Carolina Panthers on October 12 (Week 7), Johnson caught his own deflected pass and ran 3 yards for a touchdown.

[3] On the morning of the Week 13 Monday Night Football game, Johnson woke up with a sore neck and saw a chiropractor to be cleared to play.

In the season opener, a 31–7 win over Tampa Bay, Johnson threw for 4 touchdowns and 1 interception over 189 yards and completed 15 of 25 passes.

[23] Johnson returned to action in Week 9 (November 8), in a 31–24 win over the New Orleans Saints, after Cunningham injured his knee.

Minnesota finished the 1998 season a franchise-best 15–1 and advanced to the NFC championship game, where they came a field goal short of the Super Bowl against the Atlanta Falcons.

Following the season, Vikings coach Dennis Green formally named Randall Cunningham as starting quarterback and traded Brad Johnson to the Washington Redskins for a first, a future second, and a third-round draft pick.

[2] His 316 completions set a Washington team record and his 4,005 passing yards ranks fifth all-time in Redskins history.

[28] The Redskins skidded down the stretch, which saw Norv Turner fired for Terry Robiskie when the team fell to 7–6.

George would go on to have the worst stats in the league and was released for Tony Banks after the second game with a 0–2 start, while Johnson had a strong season in Tampa Bay and won a Super Bowl the following year.

In 2001, Johnson was pursued by the Baltimore Ravens in the offseason (coached by Brian Billick, his former offensive coordinator with the Vikings) but he spurned them to join the Buccaneers on a five-year contract worth $28 million.

"[31][32] He also stated that he "did nothing wrong", and that he talked to opposing Oakland Raiders QB Rich Gannon beforehand and both agreed that they preferred not to use the slick, brand-new balls that the league provided for the game.

[33] In 2003, he won the NFL's "Quarterback Challenge" competition, in which he beat Pro Bowl QBs Tom Brady, Matt Hasselbeck, Jeff Garcia, Mark Brunell, Marc Bulger and others like Byron Leftwich and Joey Harrington in a skills competition with four parts involving accuracy, speed and mobility, long distance throw, and "No Huddle.

"[1] Former teammate Sean Salisbury said that despite having a big, strong arm and a great deep ball, Johnson would tend to throw the fast and easy completion which earned him the nickname "Checkdown Charlie" among friends.

Although Johnson had good passing stats in 2003–2004 the year after the Super Bowl (3,811 yards, 26 touchdowns to break the Buccaneers' record again, 21 interceptions, and named 2003 Buccaneers MVP by the Tampa Sports Club) and 2004 (63% completion rate) they benched him the fourth game into the 2004 season because the team had gone 4–11 for the last 15 games Johnson started.

Randy Moss had been traded in March of that year, and four-time Pro Bowl Center Matt Birk was injured so Culpepper was expected to carry the offense against the top defenses in the NFL.

Many felt his quick-release style was a good fit for then-new coach Brad Childress's highly touted West Coast system.

However, in the regular season, Johnson struggled worse than Daunte Culpepper did in 2005, throwing eight touchdowns to fifteen interceptions.

Many fans grew restless for the benching of Johnson because of his conservative checkdowns, immobility, and at the same time reckless decisions which plagued the Vikings offense.

During the 2008 season, Romo suffered a broken pinkie finger on his throwing hand in week 6 against the Arizona Cardinals.

[36] Johnson ranks 63rd in career passer rating in NFL history as of January 2022, above Troy Aikman and Warren Moon, who are 71st and 77th respectively.

Johnson has also joined the popular social media platform, TikTok, where he is verified and has developed a sizable following under the username @bigbadbrad14.