On April 11, Rusev was moved to SmackDown as part of the Superstar Shake-up. On the April 25 episode of SmackDown Live, Rusev made his first appearance on WWE programming since Fastlane, appearing via satellite, and declared that he would not make his debut on SmackDown unless he was given a WWE Championship match at the Money in the Bank pay-per-view on June 18. He was not granted his request, but on the July 4 episode of SmackDown, he made his first appearance for the brand and confronted the returning John Cena, setting up a flag match for Battleground, which he lost. In August, Rusev entered into a feud with Randy Orton. They wrestled against each other at SummerSlam where Orton defeated Rusev in 10 seconds. He got his revenge the following episode of SmackDown Live, and was given the key to his legitimate hometown of Plovdiv. The mayor granted him the key to the city, as witnessed by Aiden English. However, both English and Rusev were attacked by Orton. That day was stated as "Rusev Day" and in later SmackDown Live episodes Rusev would state that "every day is Rusev Day", with the crowd chanting its name whenever Rusev and English are present. At Hell in a Cell, Rusev was defeated by Orton, thus ending their feud. On the December 5 episode of SmackDown Live, Rusev and English defeated The New Day and the two earned a spot in the fatal four-way tag team match for the SmackDown Tag Team Championship at Clash of Champions, but failed to win the titles at the event. Rusev then participated in the annual Royal Rumble match, as the #1 entrant at the namesake pay-per-view, lasting over 30 minutes, but was eliminated by Matt Hardy and Bray Wyatt. On the March 27, 2018 episode of SmackDown Live, Rusev teamed with Jinder Mahal to defeat Bobby Roode and Randy Orton, subsequently adding him to the United States Championship match at WrestleMania 34. At the event, Rusev was pinned by Mahal, losing the match. At the Greatest Royal Rumble event, he faced The Undertaker in a Casket Match, but he lost. On the May 8 episode of SmackDown Live, Rusev defeated Daniel Bryan to qualify for the Men's Money in the Bank ladder match, which was won by Braun Strowman. On the following episode of SmackDown, he won a gauntlet match to become the number one contender for AJ Styles' WWE Championship at Extreme Rules. At the event, he was defeated by Styles.
In July, Rusev Day started a feud with Andrade "Cien" Almas and Zelina Vega, thus turning them face in the process. Rusev and Lana lost a mixed tag team match to Almas and Vega at SummerSlam but defeated them in a rematch on the August 21 episode of SmackDown Live. On the September 4 episode of SmackDown Live, Rusev Day defeated The Usos and Eric Young and Killian Dain in a triple threat match to face Cesaro and Sheamus, whom they defeated on the following week's SmackDown Live to earn a SmackDown Tag Team Championship match against The New Day at Hell in a Cell, which they lost. On the September 18 episode of SmackDown Live, Rusev lost to Shinsuke Nakamura for the United States Championship after a distraction by Aiden English, after which English turned on Rusev by attacking him, thus ending Rusev Day.