Joel Keith Day (Day) appeals the 9-month prison sentence imposed upon him *556 after the district court 1 revoked his supervised release. We conclude Day’s appeal is moot because he was released from custody on May 4, 2007, and is not serving a further term of supervised release. See United States v. Johnson, 209 Fed. Appx. 608 (8th Cir. 2006) (unpublished per curiam) (dismissing as moot defendant’s appeal of his 7-month prison sentence, imposed after revocation of supervised release, where defendant had been released from custody); cf. Spencer v. Kemna, 523 U.S. 1, 6, 18, 118 S.Ct. 978, 140 L.Ed.2d 43 (1998) (declaring challenge to allegedly erroneous parole revocation moot because defendant had already served his entire sentence). Therefore, the appeal is dismissed and counsel’s motion to withdraw is denied as moot.