Contemporary

Cashbox magazine cited the single "Zelao"/"Jitterbug Waltz" from In Person as a Best Bet: "Vince Guaraldi, who scored last time out with 'Cast Your Fate to the Winds' [sic], could duplicate that success with this top-flight bossa nova follow-up stanza. The tune is a contagious, easy-going lyrical ballad with a danceable, rapidly-changing beat."^[5]

In the album's liner notes, Ralph J. Gleason praised Guaraldi's performance style, noting, "What Vince has got in his playing is feeling. This is a quality that money can't buy, practice cannot make perfect and technique tends to defeat rather than enhance. Vince sings when he plays. I don't mean he grunts or hums or even makes a noise at all. I mean his fingers sing, the music sings, and he writhes and twists on the piano stool like a balancing act in the circus."^[6]

The DownBeat critic agreed: "In a period when there seems to be a plethora of bland, sound-alike jazz pianists, Guaraldi is a refreshing relief. [He] has an exceptional knack for catching and projecting the spirit of a tune, for finding the essence of the piece, and bringing strength and validity to his exposition of it. This is honest piano playing, with no phoney soul, no gimmicks, no pretense. It's a rare quality to find on a record these days."^[7]

Retrospective

AllMusic critic Richard S. Ginell called In Person "a defining album for Guaraldi in his natural habitat" (a jazz club setting), adding that the album captures the musician "at his most winning."^[2]

Why It Matters blogger James Stafford cited In Person as capturing "the pianist in that brief moment when he was enjoying his first great national success with 'Cast Your Fate To the Wind' but hadn’t yet been transformed into a household name by Peanuts. It’s a beautiful record, filled with blues, bebop, and bossa nova, but for sheer plaster-a-smile-on-your-face delight nothing beats his take on the Mediterranean traditional song 'Misirlou'."^[8]