On Broadway James Riordan played Frank Whitworth in Jerusalem with Mark Rylance, and in The Elephant Man with Billy Crudup, Kate Burton and Rupert Graves.
The New York Daily News review of The Elephant Man called his performance "wonderful" in a "variety of roles"[1] and Curtain UP said, "The supporting cast is also well chosen, with especially good work from Jack Gilpin, and James Riordan".
As the plot unfolds, you can see the character's arrogance as well as his shame";[8] and The Star-Ledger said "Riordan is impressive as Ruskin, expansive to the point of tears as the critic describes a work of art that he finds beautiful, yet curiously chill when he encounters genuine emotions.
– I fully appreciated the artistry in Mr. Riordan's performance as the famous art critic, evincing in the play's opening moments a kind of scholarly preening that is neither ridiculous nor unattractive, a lecture-hall combination of magnanimity and authority that keeps us wondering, long afterward, precisely what we're seeing, even if we already know the story.
A lovely performance that drives this family comedy/drama from start to finish,"[17] and CurtainUp said, "Riordan is especially engaging, nimbly shifting between monologues and active romps with Hanna.
"[19] Talkin’ Broadway wrote, "Riordan plays our (anti)hero, Lamendin, to comic perfection as the character metamorphoses from a sad sack to a possessed megalomaniac.
He segues smoothly from insecure sadsack to audacious scoundrel.”[23] Riordan also appeared with David Eigenberg in the New York premiere of Neal Bell's surrealist play Ready for the River at the Home For Contemporary Theater and Art.
The New York Times wrote "the play is superbly acted"[24] and The Village Voice said "James Riordan is a serio-comic standout as the motel keeper haunted by a thrifty ghost.
The Sullivan County Democrat called the production "Triumphant" and wrote: "James Riordan steals the show quite a few times as a pissed off Cleveland fan in 1924 who had the audience chortling, and as Virgil Buell’s best friend Bud, a man dealing with the traumatic memories of war, and what it can make a man do" "[26] Broadway World wrote: "Especially versatile in various roles -- including war veteran, baseball fan, and Greek diner owner -- is James Riordan"[27] On television, he appeared as Franklin Werner in the HBO series Boardwalk Empire, in a recurring role on the final season of the television series Damages, and in recurring roles on the daytime soap operas As the World Turns and All My Children.