Born in Knoxville, Tennessee, Kirk was raised in Woodstock, Georgia and attended Etowah High School.

Early in the season he lost to Jim Herman in a playoff for the Moonah Classic and was a runner-up in the BMW Charity Pro-Am.

[5] In June he won the Fort Smith Classic, his first Nationwide Tour title,[6] and followed this up with his second win at the Knoxville News Sentinel Open in August.

[8] As a PGA Tour rookie, Kirk finished joint second to Phil Mickelson at the Shell Houston Open in April 2011.

Kirk earned his second PGA Tour win at the McGladrey Classic in November 2013, which was part of the new wrap-around season for 2014.

He finished tied for fourth in The Tour Championship, the first time he had qualified for the event, to end the season second on the FedEx Cup standings behind Billy Horschel, winning three million dollars.

The three captain's picks were announced by Tom Watson immediately after Kirk's win in the Deutsche Bank Championship.

He shot 65-66 over the weekend to finish one stroke ahead of runners-up Jason Bohn, Brandt Snedeker and Jordan Spieth.

In October 2016 Kirk was a joint runner-up in the Sanderson Farms Championship, an alternate event played opposite the WGC-HSBC Champions tournament.

1Cancelled due to COVID-19 pandemic QF, R16, R32, R64 = Round in which player lost in match play "T" = Tied NT = No tournament Note that the Championship and Invitational were discontinued from 2022.