The British artist, John Everett Millais, is most often celebrated for his role in founding the Pre-Raphaelite Brotherhood in 1848, and similarly for his works from this time. Millais also sustained a successful artistic career outside of the Pre-Raphaelite realm. It has been the tendency of recent art historians, however, to strictly divide Millais's career between his Pre-Raphaelite paintings and those that came after. In this division it becomes implicit that Millais's paintings from the Pre-Raphaelite period are innovative and even avant-garde. Meanwhile, Millais's paintings after his career with the Pre-Raphaelite Brotherhood are often considered lackluster and traditional to a flaw. This myth regarding the later phase of Millais's career negates his status as an avant-garde artist and does not acknowledge the substantial influence he had on subsequent Victorian artists. This thesis works, through a reconsideration of Millais's paintings both from his Pre-Raphaelite Brotherhood period and the years after, to dispel that myth. In specifically examining Millais's unique manner of employing landscape in his earlier and later paintings, I have proven that Millais exhibited Pre-Raphaelite tendencies, many of which were avant-garde, throughout his entire oeuvre. In further highlighting Millais's unique use of landscape and his position as an avant-garde artist, his direct influence on later Victorian artists is provided as well. In result, Millais is portrayed as a significant Victorian artist who not only made advancements in his use of landscape during his Pre-Raphaelite years, but also continued to do so in his later career. Thus, this thesis proves that Millais ultimately succeeded in contributing to the complex, ever-evolving vision of nineteenth-century British landscape.