The excellent mechanical, electrical, and thermal properties of carbon nanotubes (CNTs) make CNTs good candidates as nanofillers in the fabrication of multifunctional polymer nanocomposites. However, there are still many technical challenges to fabricate such nanocomposite. For example, one of the big technical barriers in forming CNT-polymer nanocomposite is the inefficient dispersion and alignment of CNTs in the polymer matrix. To address this issue in the fabrication of CNT-polymer composites, we have developed a synthetic approach by growing homogeneous and well-aligned CNT arrays through chemical vapor deposition, followed by infiltrating polymers into the arrays. The composite films fabricated by such an approach have well-dispersed and aligned nanotubes, which leads to much improved electrical conductivity and optical transmittance. These materials are proved promising for many potential applications such as optoelectronic and sensing devices.