In 1999, Xie began teaching at Bucknell University, while also pursuing exhibitions throughout the United States and in China; solo shows at the Scottsdale Museum of Contemporary Art (2000) and Charles Cowles Gallery (New York, 2002, 2004) soon followed, bringing him his first major critical attention. He has since had solo exhibitions at Chambers Fine Art (New York/Beijing), Anglim Gilbert Gallery (San Francisco), Nicholas Metivier Gallery (Toronto), Zolla/Lieberman (Chicago), Moatti Masters/Contemporary (London) and Gaain Gallery, (Seoul, Korea), among other venues. Xie taught at Bucknell until 2009, serving as Chair of the Department of Art & Art History from 2007–9. In 2009, he accepted a position at Stanford University, where he continues to teach. Xie's art spans diverse media, but is unified by career-long themes of the library, books and newspapers, through which he explores time, historical memory, and the role of media in perceptions of the world. Critics note in his work a balance between formal concerns, beauty and expressiveness on one hand, and on the other, conceptual rigor that addresses contemporary issues such as war, violence, power, human tragedy, and the construction of cultural knowledge. In 1993, Xie began painting library books, intrigued by the architectural quality of rows and stacks and by their conceptual potential as material carriers of ideology, cultural memory and history. He has explored this theme in many forms (decaying Chinese manuscripts, venerable reference books, crisp art archives, musical scores) found in libraries and museums from around the world. The "Library" paintings take up concepts including order and control (through systems of classification), the potential for disorder, decay, and the vulnerability and fragmentary nature of historical memory; Xie has suggested that his horror at the historical destruction of books by China's Red Guards during the Cultural Revolution, in part, played a role in his chosen themes. Xie's labor-intensive "Library" paintings depict shelved books in large-scale close-up, revealing wear, human touch, and how objects are left. He paints in what critics describe as a soft, brushy, almost impressionistic manner that captures the play of ethereal light, texture (crinkled parchment, frayed leather edges, pockmarks) and shadow; his technique achieves precision but at times dissolves into near-abstraction or blurring that suggests a camera lens or the haze of memory. Xie is sometimes linked to the realist and still-life traditions, but critics note several key differences: rather than stage tableaux, he photographs reference scenes as he finds them, composing in the viewfinder; he uses color subjectively, working in analytical near-black-and-white, warm red-brown-yellow, or almost-toxic greenish tones depending on his conceptual goals; he paints at a larger-than-life scale in which architectural presence de-familiarizes his subjects.