Daniel Klein has been hailed by the New York Times for his “stentorian bassbaritone” and “dark and steely voice.” Audiences and critics alike have found his performances imaginative, adventurous, and occasionally even downright terrifying. In 2021, Daniel returned to Opera Company of Middlebury as Thibaut d'Arc in Tchiakovsky’s The Maid of Orleans (Orleanskaja djeva), and made his Opera on the James debut as Don Bartolo in Il Barbiere di Siviglia. In February 2022, Daniel will make his debut with Intermountain Opera Bozeman as Koko (Colton) in Soren Kissel’s newly conceived The Montana Mikado. In December 2019, Daniel gained critical acclaim as Kaspar in Heartbeat Opera’s production of Weber's Der Freischütz. Critics noted his “blazing, feral intensity”, and “edgy, angry acting turned the whole drama up a notch or two. He seemed genuinely on the edge of mania—which was true of most of the characters. But with Klein, you felt it.” His previous role with Heartbeat, Don “Donnie” Pizarro, in their Black Lives Matter-themed Fidelio, received international acclaim for its powerful and timely message. Opera News remarked on Klein’s performance that it “communicated all the awful power of a little man who wants to play in the big leagues.” Recent appearances include the roles of Spencer Coyle in the New York premier of Benjamin Britten's Owen Wingrave with the Little Opera Theater of New York, Judge Moriarty in the New York premier of Huang Ruo's Bound with Fresh Squeezed Opera, the title role of Verdi's Falstaff with the International Summer Opera Festival of Morelia, Mexico; Dick Deadeye in H.M.S. Pinafore and the Pirate King in Pirates of Penzance with the Sharon Playhouse's, Marcello in La Boheme and Baron Gondremark in La vie Parisienne with Long Island Opera; Fra Melitone in La Forza del Destino with New Amsterdam Opera; Hyde in the New York Premier of Carlisle Floyd’s The Prince of Players with the Little Opera Theater of New York; and the bass soloist in Mozart’s Coronation Mass and Handel's Messiah with Garden State Symphony. Daniel created the title role Frank London’s new opera Hatuey: A Memory of Fire at the Sundance Theater Lab and appeared as the Recluse in London’s Talmudic-Klezmer Oratorio A Night in the Old Marketplace on tour in Brazil and the US.