
McCartney said of "I Will," "It’s one of my favorite melodies that I’ve written. Sometimes you get lucky with a melody, and it just comes together perfectly, and I think this is one of those. It's quite a complete tune."
In take 29, McCartney improvised by singing "won't" instead of "will," to which John Lennon responded, "Yes you will." McCartney chuckled, and the song ended at that point. This take was included in the 2018 expanded box set of The Beatles.
To mark the album's 50th anniversary, Jacob Stolworthy of The Independent ranked "I Will" 12th out of the 30 tracks on the White Album. He described the song as "crystalline proof that no one writes a love song as effortlessly as McCartney," adding that it’s hard to argue with McCartney’s choice of the song as one of his personal favorites. The song was also featured in the 1994 film Love Affair, starring Warren Beatty and Annette Bening.