Feherty turned professional in 1976 and spent most of his playing career in Europe, where he won five times and finished in the top ten twice in the European Tour's Order of Merit, placing tenth in 1989 and eighth in 1990. He spent 1994 and 1995 playing mainly on the PGA Tour in the U.S., and the best result on the tour was a second-place finish at the 1994 New England Classic. His combined career earnings exceeded $3 million. Feherty represented Ireland in international competition and captained the victorious 1990 Alfred Dunhill Cup team. Feherty played for Europe on the 1991 Ryder Cup team.

CUT = missed the half-way cut (3rd round cut in 1979 Open Championship)
"T" = tied

Since retiring, he has worked as a television personality; from 1997 through 2015, Feherty served as an on-course reporter for the PGA Tour on CBS. In 2011, he introduced a self-titled interview series on Golf Channel, and subsequently joined NBC Sports full-time in 2016.

Feherty was born in Bangor, County Down, Northern Ireland. He lives with his second wife Anita and their five children in Dallas, Texas. They have one daughter, Erin, born in 1998. Anita Feherty has two sons from a former marriage. Until 1995 he was married to Caroline Feherty, a South African beauty queen. They have two sons.

Feherty has had a long struggle with depression and alcoholism, which he publicly addressed in 2006. In an interview with Golf Magazine about his problems, Feherty said "I used alcohol to mask my inner demons". The outspoken columnist then took a shot at actor and noted Scientologist Tom Cruise, who has said that therapy and drugs are useless and that depression can be cured by physical exercise: "Actually, some sort of exercise would have helped me. If I kicked the shit out of Tom Cruise, I'd feel a lot better about myself." Along with George Lopez, Feherty hosted the Lopez-Feherty Foundation Anti-Pro-Am in November 2005.

In 2008, Feherty was hit by a truck while cycling. He suffered three broken ribs, which punctured his lung. He was hospitalised for a few days with a tube in his chest. He resumed his broadcast duties at the 2008 Masters Tournament.

In September 2005, Feherty guest-starred in the Season 6 episode of Yes, Dear ("Greg's a Mooch"). In the 18 April 2009, issue of D Magazine, Feherty was one of five Writers to comment on George W. Bush's move to Dallas. In his article, Feherty uses the article to express his support of Bush and to speak on politics. Criticism was aimed at Feherty for this suggestive comment about House Speaker Nancy Pelosi and Senate Leader Harry Reid:

At the age of 51, Feherty became a naturalised citizen of the United States on 23 February 2010.

In 1997, Feherty retired from the tours and joined CBS Sports as an on-course reporter and golf analyst. Feherty is a contributor to Golf Magazine and has his own column in the back of the magazine called Sidespin. He is also the New York Times and Booksense best-selling author of four books, A Nasty Bit of Rough, Somewhere in Ireland a Village Is Missing an Idiot, An Idiot for All Seasons, and David Feherty's Totally Subjective History of the Ryder Cup. On 21 June 2011, Feherty premiered his own weekly primetime talk show called Feherty on the Golf Channel.

In 2012, Feherty was awarded the third highest honor within the Department of the Army Civilian Awards, the Outstanding Civilian Service Award, for substantial contributions to the U.S. Army community through his work with the Troops First Foundation.

Feherty made the following controversial remarks and described his politics as such: "As for me, my politics are somewhere in the middle—and then way outside both wings. I believe in the death penalty, especially for pro-lifers, child molesters, those opposed to gay marriage, and for stupid dancing in the end zone. I believe in the abolition of estate taxes and the Pickens Plan. I'd lower the legal drinking age and raise the driving age to 18 nationwide, make Kinky Friedman governor of Texas, and make all schools, public and private, start earlier with one hour of physical exercise."

In August 2015, Feherty left CBS following his final event with the network—The Barclays. In September 2015, it was announced that Feherty would be moving to NBC Sports and Golf Channel full-time beginning in 2016, serving a similar role as he did with CBS. The deal also includes a renewal for Feherty on Golf Channel, a first-look development deal with Universal Television, and the ability for the two to collaborate on other projects, including some outside of golf.

On 29 July 2017, Feherty's oldest son, Shey, died after a drug overdose on his 29th birthday.