Breakthrough received generally mixed to favorable reviews from contemporary music critics, with some praising its rich texture and for being a consistent album with catchy tracks, while others dismissing its title and finding issues with some of the song's lyrics.

The second single, "I Never Told You", was released on February 16, 2010, and found similar success on the Adult charts, while being more moderate on the Billboard Hot 100.

After the success of her debut album, Coco (2007), which sold over five million copies worldwide and spawned her biggest hit, "Bubbly",[2] Caillat went on tour for two years to promote the record.

[4] In early 2009, to achieve her desired sound, Caillat set up a "writing camp" in Kauai's Hanalei Bay in Hawaii and invited such colleagues as Jason Reeves and Mikal Blue, who co-produced her first album, Coco, as well as experimented working with new songwriters and producers such as Kara Dioguardi, John Shanks and Greg Wells.

[6] Caillat stated that she "wanted to make music that people could listen to while driving on a long road trip, while dancing at a party with friends, while laying out at the beach or sitting at their desk at work.

[8] "You Got Me" and "Fallin' for You" were considered "innocent love songs" that "capture the breathless first blush of infatuation",[6] with the former featuring quirky organ rhythm and a "string-laden lush pop chorus that adds horns the second time around"[8] and the latter has a midtempo gently rocking beat.

[8] "Droplets" and "Runnin' Around" finds Caillat getting cold feet, with the former being a duet with Jason Reeves and the latter having an "airy 'Everybody Wants to Rule the World' vibe.

[6] "Fearless" has an electronic beat[8] and finds the singer "clinging to her self-respect as a former [lover] walks away, while "It Stops Today" "focuses on intentionally facing our deepest hurts.

"[6] The final track on the standard edition, "Breakin' at the Cracks" was considered "the most mournfully earnest song here, as [she] repeatedly pleads, 'I need you back'.

[4] Caillat performed the album's first single "Fallin' for You" in many television shows, as well as a set on CNN.com Live and Walmart Soundcheck.

[10] "Don't Hold Me Down" was featured in the film Morning Glory (2010), while the instrumental of "Begin Again" was used on the TV series Life Unexpected.

The "lilting" mid-tempo ballad "features an instantly catchy chorus and toe tapping melody," as defined by Melinda Newman of HitFix.

[21] In a positive review, Michael Lello of PopMatters noted that on the album Caillat "wisely builds upon her strengths— the aforementioned disciplined singing approach and girly topics— rather than enter drastic new territory."

"[8] Monica Herrera wrote for Billboard that the album is "warm and inviting", however noted that it "never quite lives up to its title, but highlighted the song "Fearless" for diverging from the formula and offering "delightful relief" and "a taste of what could be if the singer were to dig deeper.

"[9] Lamb however noted that the album is "a little slicker, a little more polished" than its predecessor and the "final result is remarkably slick, cohesive and similar sounding, but that isn't always a great thing.

"[9] Jim Farber of New York Daily News noted that "Caillat's sweet old-fashioned melodies are no 'Breakthrough,' but second album still charms.

"[20] Q magazine called it "[h]ardly essential, but brimming with late summery charms,"[21] while Trey Spencer of Sputnikmusic was more positive, writing that "Colbie’s soothing vocals, the warm sound of the music, and the memorable choruses are all well worth listening to this for when the mood for something easy hits you."

"[22] Though being critical with Caillat's songwriting skills, Sal Cinquemani of Slant Magazine considered the album "a marginal improvement over her debut, Coco.