In the UK, the song spent 19 weeks within the top 40 before peaking at number one in early November 2014; it became Sheeran's second number-one single there.

Wadge also co-wrote the song "Gold Rush", a track on the deluxe version of Sheeran's debut album, + (2011).

[5] According to Wadge, the lyrical content resulted from her and Sheeran's talking about "everlasting love", inspired by the circumstances relevant at that time.

[12] Sheeran revealed that he also had his grandparents in mind and maintaining love in old age ("'til we're 70" in the lyrics), and the early version of the chorus was "I'm singing out now" before it became "I'm thinking out loud".

[16] In the lyrics, Sheeran reflects on "getting older and fidelity and love in a fairly conventional context", according to Eric Clarke, professor of music at University of Oxford.

Andrew Unterberger of Spin wrote that "the gently loping four-note bass pattern and crisp '70s soul drums absolutely smack of the Gaye classic, as do the embrace-insistent lyrics and general candlelit-bedroom feel".

[22] Prior to the album release, Sheeran debuted "Thinking Out Loud" on 24 May 2014 by performing it live on the British music television show, Later... with Jools Holland.

According to Sheeran, no one from his record label wanted to release "Thinking Out Loud" as a single, favouring over "Photograph" as the "big song".

"Thinking Out Loud" was issued on 7" vinyl exclusively as part of the Black Friday Record Store Day, which was celebrated on 28 November 2014.

[25] The vinyl record included, as a B-side, the live version of "I'm A Mess" which Sheeran performed at the Lightship 95 studio.

[27] Lauren Murphy of The Irish Times noted that the "injection of blue-eyed soul" on the song is "enjoyable", and that it "makes Sheeran's aptitude for melody difficult to dismiss".

[28] Jim Beviglia of the American Songwriter thought that although "tidy", "Thinking Out Loud" comes "toothless" compared with the "daring confessionals" Sheeran made on the other songs.

[29] The Washington Post writer, Allison Stewart, has hailed the song as "a blatant and mercilessly effective bid for 'I'll Be'-style wedding-song immortality".

[30] Billboard magazine's Jason Lipshutz, commented that Sheeran "pushes this bold stab at romance past its sappiest moments, and ends the album on a likable note".

[22] Jamieson Cox of Time wrote that "the album's greatest moment by a country mile is relegated to its penultimate slot", referring to "Thinking Out Loud".

[34] On 18 September 2015, the British Phonographic Industry certified the single triple platinum for combined sales (including streaming points) of 1,800,000 units.

[38] On other specific US charts, "Thinking Out Loud" reached number one on the Billboard Adult Pop Songs for the week ending 21 February 2015, marking Sheeran's first.

[42] In the UK, Sheeran's native country, "Thinking Out Loud" claimed the record for the most streams in a single week in December 2014.

In April 2015, the song ranked as the most popular based on the 2.8 million sleep-themed playlists created by Spotify users.

[45][46] The Guardian columnist Tim Dowling suggested that the report indicated "very popular, slightly mellow songs that keep cropping up on sleep playlists" but not a list of a "carefully curated journey to unconsciousness".

[50] Unlike Sheeran's earlier videos, where he assumed a low profile, he took the lead role on "Thinking Out Loud".

He also performed the song at the 57th Annual Grammy Awards on 8 February 2015 along with John Mayer, Questlove, Adam Blackstone, and Herbie Hancock.

[60] On 28 April 2015 episode of The Tonight Show Starring Jimmy Fallon, actor Jeremy Renner, known for his role as Hawkeye in the Avengers movies, performed on piano and sang a song captioned by Fallon's show on YouTube as "Hawkeye Sings About His Super Powers".

The lyrics suggest that Hawkeye feels defensive compared with the other Avengers as he was the only mortally human one in a team of superhuman or enhanced heroes: "But listen, I've got powers too; they're pretty sweet.

The lyrics are an appeal by Foster's character, Nathaniel Plimpton III, to series protagonist Rebecca Bunch (Bloom) to have sex whilst trapped in an elevator.

[64] Two years later, on 28 June 2018, Ed Sheeran was again sued on similar grounds, this time for $100 million in damages by Structured Asset Sales, owners of one-third of the copyright to "Let's Get It On".