Jack David Clancy (born June 18, 1944) is an American former professional football player who was a wide receiver for the Miami Dolphins in 1967 and 1969 and for the Green Bay Packers in 1970.

At the University of Michigan, Clancy started as a quarterback, switched to halfback, returned punts and kickoffs, and became a star as an end.

At the time of his graduation, he held the school records for most receptions and receiving yards in a career, season and game.

Traded to the Green Bay Packers in 1970, Clancy was unable to return to his prior form after the knee injuries.

[7][9][10] As a result of the injury, Clancy missed Michigan's Big Ten championship season in 1964, as Jim Detwiler took over his halfback spot.

[5][11] In his first game at the end position, Clancy made what was described as "a circus catch" in the endzone on a pass from quarterback Dick Vidmer.

[13] Clancy set the Big Ten receiving record in against Wisconsin, catching a 52-yard touchdown pass from quarterback Wally Gabler on Michigan's first offensive play.

[14] At the time, the Associated Press reported: "What makes Clancy's record so much more impressive is the fact that he came to Michigan as a quarterback, switched to halfback and won a spot there two years ago and then turned to end this season.

And with Michigan's reputation for always having talented ends—Benny Oosterbaan, Lowell Perry, Ron Kramer and John Henderson among them—Clancy's feat takes on even more brilliance.

[37] However, Clancy suffered a ruptured ligament in his left knee shortly after catching a pass against the Baltimore Colts in the final pre-season game on August 31, 1968.

[30] Clancy watched the Dolphins from the sidelines with his leg in a cast, as Karl Noonan took over at split end and led the AFL in touchdown catches in 1968.

"[36] After a season on crutches, the UPI reported: "The former rookie wonder wants to get back under quarterback Bob Griese's passes, to reclaim his billing as the Miami Dolphins' top receiver.

"[36] Clancy's comeback appeared to be on track in early November, as he was a close second among Miami receivers with 21 catches for 289 yards.

[38] However, the comeback was cut short on November 2, 1969, when he suffered torn ligaments, this time to his right knee in a loss to the New York Jets.

[41] In May 1970, Clancy was traded by the Dolphins to the Green Bay Packers for tight end Marv Fleming.

[41] Clancy had begun a business selling real estate in Miami during the offseason, but he also had ties to Green Bay.

[42] Wisconsin columnist Lee Remmel said Clancy "surveys the football scene with a pair of cool, calculating blue eyes and a computer-type mind.

[46] Clancy finished fifth in receptions on the 1970 Packers, behind Dale, tight end John Hilton, running back Donny Anderson, and even fullback Jim Grabowski.

[48][49] In all, Clancy played in 36  games for the Dolphins and Packers, compiling professional career totals of 104  receptions for 1,301 yards.