Vaccines are a crucial public health countermeasure. New vaccine platform technologies are continually being developed, enabling more efficacious vaccines that target a diverse array of pathogens. Exemplified by the SARS-CoV-2 pandemic, research programs developing nucleic acid vaccine platform technologies – both DNA and mRNA – have surged in recent years. DNA vaccines offer several advantages relative to other platforms, including simple manufacturing, rapid development timelines, and cold-chain independence. However, while DNA vaccines have elicited strong T cell responses in the clinic, their ability to induce potent humoral immune responses has been limited. Improving the serological potency of DNA vaccines while maintaining the strong T cell response profile would be of interest for future vaccine development. Here, we explored two approaches to enhance DNA vaccine-induced immune responses in vivo. We first examined whether scaffolding both antigen and a cytokine on a self-assembling nanoparticle scaffold could augment germinal center responses to DNA vaccines. We demonstrate that that engineering IL-21 to be co-displayed to a self-assembling nanoparticle immunogen improves germinal center response frequency and breadth, increases antigen-specific serum antibody titers, and is dose-sparing relative to antigen-only nanoparticles. We next studied whether changes to DNA vaccine delivery utilizing lipid nanoparticles (DNA-LNPs) could enhance immunogenicity. We hypothesized that a limitation in developing effective lipid-mediated delivery of plasmid DNA is the larger size and increased number of phosphates relative to mRNA. We modulated the relationship between the lipid components and DNA to improve the biophysical profile and immunogenicity of DNA-LNPs. Relative to benchmark mRNA-LNP and adjuvanted recombinant protein vaccines, DNA-LNPs induced comparable humoral and superior T cell responses after a single immunization in both mouse and rabbit models. Taken together, these approaches demonstrate that modulation of both the encoded DNA vaccine sequence through nanoparticulate display of both antigen and adjuvant as well as formulation modifications can improve adaptive immune responses to DNA vaccines. These developments provide new tools that enhance the potency of DNA-encoded immunogens, providing insight into continued refinement of this platform.