Just before entering Milwaukee Art Museum’s new show, "Thomas Sully: Painted Performance," curator William Rudolph noted that it’s the first retrospective of this 19th century American painter’s work in three decades and the largest in a century.

As Rudolph – who is the art museum's Dudley J. Godfrey Jr. Curator of American Art and Decorative Arts – set the stage, his passion for the artist and this exhibition, which he has spent eight years working on with the Philadelphia Museum of Art’s Carol Eaton Soltis, was palpable.

But, I admit, I was steeling myself to be underwhelmed. Surely, not because the work isn’t worthy, but because 19th century American portraiture rarely gets my blood flowing.

In the end, Rudolph – and Sully, of course – won me over and pretty much right from the start, thanks to the wise placement in the first gallery of a quartet of paintings of stage actresses that find Sully infusing his work with his trademark movement. But also because three of the works have intriguing areas that feel unfinished and ethereal, as if capturing on canvas the mysterious swirling magic of the theater.

Sully's more formal portraits of bankers and non-theater personalities rarely make use of this effect, though a portrait of Andrew Jackson – who perhaps possessed a similar mythological vibe – does make use of the technique.

Indeed, these works also show us part of what made Sully unique: his focus on the theater – though, certainly, he painted many things unrelated to the stage. Rudolph says that it’s a world that Sully knew intimately through his parents, but also first-hand.

"Sully grew up in theatrical family. His parents were rich actors who came to this country when Sully was a child with the rest of his siblings. They were invited to come manage a theatrical company throughout the southeast and Midwest," Rudolph says. "And so Sully trained as an actor and so did many of his siblings. He ultimately chose the visual arts his oldest brother was a painter who was one of Sully’s teachers.

"The first people he really painted were actors and actresses in a role or being expressive in theater."

Born in England in 1783, Thomas Sully moved to the United States with his family in 1792 and settled in South Carolina. He studied painting briefly under Gilbert Stuart and became a professional painter while still in his teens. In 1809 he spent nearly a year in Europe, where he visited art museums and studied with Benjamin West.

When his brother died, Sully married his sister-in-law and lived in fear of prosecution for incest in Virginia and so moved to New York and then continued on to Philadelphia, where he lived until his death in 1872.

There, he made a career in painting, in part by following trends and catering to them. He also learned to paint for the engraving and gift book markets to keep funds coming in.

Some of these works are in the Milwaukee Art Museum show – especially portraits of his son and daughter created as sort of archetypal images of children that could be reproduced in a number of settings. The portrait of his son, seen above, is one of the show’s most sentimental and effective works.

"His career really spans the 19th century," says Rudolph. "He has a huge career. There were 2,361 documented works by Sully himself. He kept voluminous records. He is an art historian’s dream in the sense that he kept a register, he kept journals ... price, when he began a work, when he completed the work, when it was paid for, which gives a fascinating window into how long people took to pay, estimates of work he donated to people, so he had that sense of what he put into it and what he valued it at.

"He’s a fascinating example of what it meant to be a working artist for the majority of the 19th century in the United States."

The fact is, if at first glance, Sully’s work appears staid and dated, go back and look again more closely and you’ll see things you missed, subtleties that may lead you to reassess the work. That’s what happened, Rudolph says, even for the show’s curators.

"It certainly made us think about Sully in new ways, and we hope that if you spend a little bit of time on this show that it will make you think about him in different ways and we hope that it will connect with visitors."

The show isn’t chronologically arranged – "it’s very hard for historians to identify Sully by decades because he would to different ideas over and over again," says Rudolph – but rather displayed in thematic sections on brightly colored walls.

In the center of the exhibition, there is an open space that affords glimpses into a 360-degree panorama of gallery areas, giving visitors the sense of the volume and variety of Sully’s work.

"The portraits," Rudolph says, "reveal human exploration. The fact that we have people showing themselves off to the world, and Sully seems to do that in a much more dramatic and vivid way than many of his colleagues."

"Thomas Sully: Painted Performances" is on view through Jan. 4, 2014 and heads to the San Antonio Museum of Art for a three-month run beginning Feb. 5.

A full slate of Sully-related events and programming can be found here.