[6] Upon completing her research fellowship, Willer applied for an R01 grant from the National Institutes of Health to propose a statistical study to search for genes related to blood cholesterol levels.

Alongside graduate students Ellen Schmidt and Sebanti Sengupta, her research team found 157 gene-changes in human DNA that alter the levels of cholesterol and other blood fats that could lead to new medications.

In 2018, Willer launched the Michigan Racial Equality and Community Health (MREACH) program, a biobank "to help drive future genetic research towards studying diseases that disproportionately affect minorities and ensuring that future prevention strategies are optimized for minority individuals.

"[13] She was also appointed to work on the genome-wide association study, a team which identified 111 loci, 80 of them new, for Atrial fibrillation (A-fib).

[15] During the COVID-19 pandemic, Willer and her research team identified 76 notable variants with potential, 11 of which were previously unreported, genes as possible future targets to address cardiovascular risk without affecting the liver or causing other metabolic disorders.