The cover version by , released in February 1968 (officially, it was the B-side of "Somebody Tell Me My Name", which was written by Dennis Fridkin and Geoff Levin) ( 2078) was a No.14 hit in the USA and went to No.1 in Japan (Capitol CR-1960). In 1968 Capitol released People!'s version in Mexico (Capitol 6353); Australia (Capitol 1729); Canada (Capitol 2078), where it reached No.7 in May 1968; Brazil, backed with "1000 Years B.C." (written by and Robb Levin) (Capitol 7C-11072); France (Capitol CLF 2078); Germany (Capitol 23827); Japan (Capitol CR -1960); United Kingdom (Capitol 15553); and Singapore (Capitol CL-15553). An was released in Spain (Capitol EAP-21103). After extensive promotion by the band and its manager, and industry advertising by Capitol, "I Love You" quickly became a hit single, selling more than one million copies, and reaching a peak of No.14 on the Hot 100 on 14 June 1968 and reaching No.13 on the Top 100 Singles Chart on 29 June 1968, and became a #1 single in several markets, including Italy, Israel, and Japan. According to the liner notes of the 2006 album, People!'s version of "I Love You" could have topped the US national charts if not for industry rivalries:
"It was No.1 in Japan. It was big everywhere. Israel, South Africa, England, Scandinavia, Argentina and America where it actually hit No.1 in every 'market' all over the country, but not in the same week. and had two competitive companies who did exactly the same thing. For an expensive membership each would advise radio stations on what was bubbling up and was going to be a popular release to put into rotation on the radio . But People! was produced by , an upstart who broke all the rules of AM and could predict much more accurately what was going to be a hit. So any radio programmer could take a look at Hunter's playlist, several weeks ahead of the nation, and pick the hits for free. Gavin and Drake decided to bury Hunter and one way was to advise programmers NOT to play "I Love You." "It's not going to be a hit." was their steady message for the four months during which "I Love You" fought its way to the top of every chart. A sad story. But a funny one, because People! was able to do a concert in every city while their single was the hottest thing on the local charts. Most bands can only do concerts for a week as their song hits No.1 and then is pushed off the charts by a song, or even a song. So People! followed the path that the song laid down and had the biggest and longest thrill ride any band can have. It was a freakish phenomenon and one that never happened again. The suppression and attempts of Gavin and Drake spun the band into the majors and the band toured with and would have kept on going. But Larry [Norman] left the band on the day when Capitol followed up the little hit that could with a revamped version of the album for its premier release. Had the song been left on its own, unopposed, it would have sat atop the national charts at #1 for several weeks according to the overall tally in the end. Had Larry stayed in the group, who knows what might have happened".
After the release of their single "I Love You", People! toured extensively, appearing three times on 's , and also on 's . Billboard ranked People!'s version as No.53 in their top 100 songs for 1968, while it was ranked #75 in the Cashbox annual charts.
In 1966 "I Love You" was included in an album that is now known as the album that was only released in the Netherlands and Japan. After the popularity of "I Love You" and two other Zombies songs in the Philippines, The Zombies sold out 10 concerts at the in , near Manila, in March 1967. Soon after their return from the Philippines, their contract with Decca lapsed and, although they recorded a further LP, , for their new record label in the summer of 1967, the band disbanded once that album was finished (and before its 1968 release in the UK and US). However, after the chart success of the cover version of "I Love You" by American band , in mid-June 1968 Decca reissued The Zombies' original version in the UK, backed with "The Way I Feel Inside" (Decca F12798). However, it again failed to chart.