His portraits focus on the intellectual circles of the early twentieth century. He painted figures such as the physicist Hendrik Lorentz. His work also includes portraits of artists David Oyens and Adolf Le Comte. As a practitioner of Dutch realism, Buisman used a restrained colour palette and precise brushwork to capture the personality of his subjects. He avoided dramatic lighting or stylised backgrounds. Instead, he relied on careful observation to produce a faithful likeness that conveyed the professional standing of the sitter.

Modern collectors value Buisman for his technical skill and the historical interest of his subjects. His work provides a visual record of Dutch academic and artistic life. These portraits are quiet additions to a room. They offer a sense of tradition without the clutter of more ornate historical styles. The clarity of his compositions makes them suitable for contemporary interiors that prioritise clean lines and realistic subjects.