Ed Begley Jr has earned a whopping Emmy nominations in his illustrious career, but it’s Heyden Begley who commands the El Portal Theatre stage as the brilliant but emotionally fragile daughter of a mathematical genius gone mad in David Auburn’s Pulitzer Prize and Tony Award-winning Proof.

When we first meet Begley Jr’s university professor Robert and his gifted daughter Catherine on her 25th birthday, conversation has turned to Robert’s long history of mental illness and Catherine’s fear that she may have inherited more than just a mathematical mind from her father—a fear quickly understood when Robert lets slip a bombshell (at least for us in the audience), one that would seem to offer proof that Catherine might in fact be as loony as dear old Dad.

Meanwhile inside Robert’s house, Catherine has given Hal (Kelly Sry), her father’s former student, permission to go through his professor’s notebooks in hopes of discovering if perhaps, during a period of remission, Robert wrote down another of those brilliant proofs he had come up with so often as a young man.

So far, however, Hal has unearthed nothing, and Catherine begins to suspect that the reason for his search may be less altruistic than he claims. Might her father’s student not be looking for a proof to pass off as his own and thereby insure himself a lucrative future in his chosen field?

Complicating matters is Catherine’s older sister Claire (Kate Woods), a successful New York financial analyst who has arrived back at the family homestead aiming to convince Catherine to relocate to the Big Apple and get the psychiatric help she is convinced her sister needs.

Will Catherine accompany Claire back to New York or stay put in Chicago where a smitten Hal has begun to pierce her emotional armor?

And more importantly, will the contents of a locked drawer in her father’s desk help or hinder Catherine’s quest to prove her sanity and her genius, both to herself and to the outside world?

Unearthing the answers to these questions is just one reason why Proof scored its playwright pretty much every award possible upon its Broadway debut in 2000.

So are the rich characters Auburn has created, and for the most part, the performances elicited by director Stuart Rogers do these roles the justice they deserve.

As the granddaughter of Oscar-winner Ed Begley and the daughter of Begley’s TV star son Ed Jr, Hayden Begley has quite a legacy to live up to, but live up to it she does in a dynamic, multi-layered performance as the brilliant but insecure Catherine.

Opposite her as Catherine’s bossy but caring sister, the terrific Woods has us believing in Claire’s good intentions while rooting for her to fail in her efforts to relocate her younger sibling to NYC.

Add to that the nerdy charms of the ever so appealing Sry, and you’ve got a supporting cast that more than lives up to the demands and expectations of the roles Auburn has given them to captivate an audience with.

Less captivating is the production’s above-the-title star, Begley Jr’s trademark deadpan delivery dialed down here to a virtual monotone, and whether by choice or as the result of his ongoing battle against Parkinson’s, the role of Robert calls for more fire than ice.

Performances aside, director Rogers breaks the rules when he allows Robert to hand Catherine a champagne bottle and otherwise interact physically with his environment in the opening scene.

In addition, though I appreciate the many details of Joel Daavid’s back porch and backyard set, it seems an unnecessary distraction to have Robert’s house literally fall apart before our eyes in present day sequences, and while I appreciate the additions of 2026-style cellphones and texting to bring Proof up to date, they don’t gibe with a script that has one character referring to “phone sex operators.”

I’m also not all that fond of having rock/pop songs link scenes in place of a more mood-establishing instrumental score.

Also, while Alexandra Fatovich’s costumes do suit each character, would Catherine really go out into blistering Chicago cold bareheaded and without gloves?

On the plus side, I have absolutely nothing but good things to say about Matt Richter’s pitch-perfect lighting design, and Cricket S. Myers’ sound design amps spoken voices to perfection.

Proof is presented by Jason Jeske and produced by Betsy Zajko, Lexi Sloan and Sara Fenton. Beckett Rogers is associate producer. Megan Raitano is production stage manager and associate director. Isabel Olivia Marcus is assistant stage manager. David Elzer is publicist.

As a benefit to raise money for the Michael J. Fox Foundation for Parkinson’s Research, Proof’s heart was most definitely in the right place. I only wish it had been the all-around brilliant production this play deserves.

El Portal Theatre, 5269 Lankershim Blvd., North Hollywood.
www.elportaltheatre.com

–Steven Stanley
July 26, 2026
Photos: Jeff Lorch

Tags: David Auburn, El Portal Theatre, Los Angeles Theater Review