McKenna was raised in a musical family and wrote her first songs as a teenager, though it wasn't until her late twenties that she began performing on Boston's folk circuit. After releasing her debut, Paper Wings and Halo, in 2000, she signed with indie Signature Sounds and released three more albums over the next four years, including 2004's acclaimed Bittertown. While her reputation as a quality songsmith had already netted her a publishing deal with Nashville's Harlan Howard Music, her fortunes changed dramatically when country star Faith Hill covered three of McKenna's songs on her 2005 album Fireflies. Hill's album topped both the country and pop charts and the increased exposure soon earned McKenna a record deal with Warner Bros., which reissued Bittertown later that year.

While the Warner deal would only yield one new album in 2007's Unglamorous, Universal Music signed McKenna to a publishing deal the following year and by the decade's end, other major artists like Tim McGraw, Mandy Moore, and Vance Gilbert had recorded her songs. In addition to her successes as a songwriter, McKenna continued to record her own albums, earning acclaim for releases like Lorraine (2011), Massachusetts (2013), and Numbered Doors (2014). As a songwriter, she remained in high demand, writing for Keith Urban, Hunter Hayes, Alison Krauss, and Little Big Town, among many others. Several of her songs proved to be major hits with Hayes' "I Want Crazy" topping Billboard's pop chart and Little Big Town's country smash "Girl Crush" earning McKenna her first Grammy and CMA awards. Throughout her career, she has continued to call Boston home, commuting to and from Nashville to write and collaborate, while choosing to live outside of Music City's bubble. After signing a new deal with Creative Nation in 2015, she hooked up with Nashville maverick Dave Cobb, whose organic production style has been parlayed into critically lauded albums by artists like Sturgill Simpson and Jason Isbell. The result was 2016's more intimate The Bird & the Rifle, which featured her own version of "Humble and Kind," a country hit she'd provided to Tim McGraw earlier in the year. McGraw's version also helped her earn a second consecutive CMA award for Song of the Year. ~ Timothy Monger