John Joseph Harrington (born October 21, 1978) is an American former professional football quarterback who played in the National Football League (NFL) for seven seasons. He played college football for the Oregon Ducks, winning Pac-10 Offensive Player of the Year as a senior, and was selected third overall by the Detroit Lions in the 2002 NFL draft. Unable to duplicate his collegiate success, he left the Lions after four seasons. He spent his final three seasons as the primary starter for the Miami Dolphins and Atlanta Falcons and as a backup with the New Orleans Saints.

Harrington was born and raised in Portland, Oregon. He graduated from Central Catholic High School in Portland, and finished his high school career with more than 4,200 yards and 50 touchdowns rushing and passing.

Harrington's grandfather and father played quarterback for the Universities of Portland and Oregon, respectively, and upon hearing of Joey's birth, legendary Oregon Ducks' coach Len Casanova jokingly sent his parents a letter-of-intent.

Harrington is a graduate of the University of Oregon, and was a three-year starter on the Oregon Ducks football team. In his senior season at Oregon, he threw for 2,415 yards and 23 touchdowns, and he finished his college career with a 25–3 record (including bowl wins against #12 Texas and #3 Colorado), 512 completions in 928 attempts (55.2%), 6,911 passing yards, 59 touchdowns, 23 interceptions, and 210 rushing yards and 18 scores on 145 carries. A business administration major with a 3.23 GPA (twice earning honors with a 3.34 GPA), Harrington's 7,121 yards of total offense rank sixth in University of Oregon history.

Harrington finished fourth in the voting for the Heisman Trophy in 2001, following a campaign for the award that included a billboard in Times Square promoting him as "Joey Heisman." He earned numerous honors, including first-team All-American, Pac-10 Offensive Player of the Year, and second-team honors from The Sporting News. He was one of five finalists for the Johnny Unitas Golden Arm Award in 2001. EA Sports selected him for the cover of the 2003 edition of their NCAA Football video game series. Harrington was given the nickname "Captain Comeback" among fans for his ability to lead Oregon to victory in late game situations, accumulating a record of 11–2 in games in which the Ducks trailed or were tied in the fourth quarter.

Harrington was selected by the Detroit Lions with the third pick overall in the 2002 NFL draft and signed his contract in mid-July. He was cited by head coach Marty Mornhinweg as the quarterback of the future, though wasn't ready to name him the starting quarterback, instead placing him behind starter Mike McMahon and backup Ty Detmer. In his first preseason game, Harrington threw two interceptions, including the game-losing pick-6 versus the Baltimore Ravens. In his next preseason game, Harrington threw for 236 yards and two touchdowns in the 23–24 loss. Harrington debuted in a Week 1 blowout loss versus the Miami Dolphins, completing 4 out of 11 passes for 41 yards. After Week 2, Harrington was named the starter ahead of McMahon. Making his first start in the Week 3 matchup and opening debut of Ford Field versus the Green Bay Packers, Harrington threw for 182 yards and 2 touchdowns to 4 interceptions. Down 17 late, the Lions rallied back with two touchdowns, including a 52-yard touchdown pass from Harrington to pull within 3. Harrington had a chance for a game-winning drive with 1:03 left before throwing an interception to seal the loss. Harrington got his first NFL victory with a 20–7 win over the New Orleans Saints, throwing for 267 yards and a touchdown with no turnovers or sacks. In Week 6 versus the Minnesota Vikings, the Lions were down 24–31 and at Minnesota's 8-yard line. However, Harrington threw a pass into the endzone that was picked off, leading to a Lions loss. In the Week 15 game versus the Tampa Bay Buccaneers, Harrington was taken out due to an irregular heartbeat, leading him to miss the final two games of the season. He underwent a procedure to fix the irregular heartbeat a day later. In fourteen games played, Harrington finished his rookie season passing for 2,294 yards, 12 touchdowns, and 16 interceptions while completing just over 50% of his passes, and a 3–9 record.

In the season-opener, Harrington threw for 195 yards, four touchdowns, and no interceptions to defeat the Arizona Cardinals 42–24. However, the Lions proceeded to go on a six-game losing streak as Harrington threw for 12 interceptions to 4 touchdowns in that time. In the Week 12 game versus the Minnesota Vikings, Harrington threw for 167 yards, 1 touchdown, and 4 interceptions, including two back-to-back pick-6's to fall 14–24. In the season-finale, the Lions upset the one-seeded St. Louis Rams as Harrington threw for 238 yards, 3 touchdowns and an interception in the 30–20 win. Harrington finished his season throwing for 2,880 yards, 17 touchdowns, and a league-leading 22 interceptions.

Facing the David Carr-led Houston Texans in Week 2, Harrington tossed for 176 yards, 3 touchdowns, and 1 interception while leading the Lions to their first 2–0 start since the 2000 season. In Week 7, Harrington threw for 230 yards and 2 touchdowns while leading the Lions to a 28–13 win and a 4–2 record. However, the Lions would go on another losing streak, losing five-straight before their next win in Week 13 against the Arizona Cardinals where Harrington threw for 196 yards, 1 touchdown, and 1 interception in the 26–12 win. In the week before, Harrington was benched in the second half for McMahon after throwing for 156 yards in a blowout 9–41 loss against the Indianapolis Colts. In Week 14 against the Green Bay Packers, Harrington completed 5 of 22 passes for 47 yards as the Lions gave up a 13–0 lead. Lions head coach Steve Mariucci was hesitant to name a starter for the next game, but stuck with Harrington. Harrington finished his season with a career-high 3,047 yards, 19 touchdowns, and 12 interceptions while completing 56% of his passes.