J. Cole at DAR Constitution Hall. (Kyle Gustafson/For The Washington Post)

It’s been a full birthday week for rapper J. Cole, who turned 29 on Tuesday. He launched his own Dreamville label imprint and released a new mixtape, “Revenge of the Dreamers.” During a show at New York’s Madison Square Garden Theater, Cole’s mentor, Jay Z, presented him with a gift — the original Roc-A-Fella necklace that Jay used to wear in the 1990s.

The eventful week might explain Cole’s scattered performance at DAR Constitution Hall on Thursday night. Maybe he was tired. Or tipsy. Cole took several large swigs from a Hennessy bottle during the 90-minute gig. “I just had a birthday,” Cole reminded the young crowd. “So I’ve been drinking a lot of Hennessy, man. A lot.” When he wasn’t sipping ­cognac, he sat on the stage steps or on a black stool at the stage’s center. Sure, that made the show feel intimate — he referred to the fans as “family” — but it made Cole look lethargic. Throughout the show, Cole halted the energy with meditative chatter and an ill-timed shtick with collaborator Bas, who joined Cole onstage for “Lit.”

Cole was decent when he got around to performing music, highlighted by a fiery rendition of “Trouble,” a standout from his 2013 album, “Born Sinner.” There were times when it seemed the rapper would tip over with excitement. With each standout lyric and climactic beat drop, Cole ran briskly along the platform, his diamond-encrusted Jesus chain swaying vigorously against his all-black outfit. He frequently jumped backwards and stumbled slightly, as if the force of his own rhymes were too strong for his rail-thin basketball frame. Songs such as “She Knows” and “Forbidden Fruit” succeeded, but that was mostly due to spirited fans who recited many of Cole’s lyrics for him.

The rapper showed flashes of intrigue, but the concert stalled amid a lack of focus and cohesion. There were moments when Cole performed to prerecorded studio music instead of with the septet behind him. When accompanied by the live band, the tunes didn’t always translate well to the venue’s sound system. Cole took requests near the set’s conclusion — the fans chose “Villuminati” — but even that took a while to pull together.

It was ultimately an uneven showing for the birthday boy. Cole attempted to make things cozy but they ended up feeling disjointed. There were just too many pauses and false starts, which drained the intensity and led to its collapse. If Cole is this sluggish at 29, how will he handle his 30s?

Moore is a freelance writer.