Born in Rotterdam, Netherlands, Mullaard was the youngest of seven children. His father was a marble painter and his great-grandfather was a painter of art. However, at the urging of his father, Mullaard learned a trade and became a plumber.

In 1931 Mullaard married Jo Geelhoed, they remained married for sixty years until his death in 1991. While living in Hillegersberg-Schiebroek, Mullaard joined the revolutionary OSP (Independent Socialist Party (Netherlands)) and became very active in anti-Nazi demonstrations.

It was not until 1936 that Mullaard began to paint. Entirely self-taught Mullaard was active as a painter and sculptor between 1936 and 1981. Over the course of his life, he lived and worked in Hillegersberg, Ermelo, Groningen and Bilthoven.

In the spring of 1942 Mullaard befriended the painter Maarten Jungmann, who became his lifelong friend and mentor. Jungmann had great appreciation for Mullaard’s art. Jungmann nominated Mullaard to join the Pulchri Studio (the leading Dutch art society/art institution of the day) as a working member. However, the application was not successful for reasons of political and artistic differences of opinion between Mullaard and the admission committee. On the committee were Gidding and H.F. Boot (ardent members of the Nazi-installed Chamber of Culture) and they rejected Mullaard’s application to the Studio on the basis that it did not meet the Nazi Party’s prescribed parameters of artistic expression. This was war time after all.

Despite being obviously upset, Mullaard defiantly declared to Jungmann “they can reject me all they want, but I will still keep painting!”

In 1943 Mullaard and his wife moved to Ermelo, in order to be shielded from German interrogation and imprisonment. Though Mullaard kept painting during this time, this was a time of social unrest and instability. Mullaard had been imprisoned for two weeks due to his involvement in anti-Nazi demonstrations, and spent much of his time involved in underground work helping people flee Nazi persecution.

At the liberation of Holland, Mullaard painted and gave away the portraits of two Canadian military leaders, he also gave away 15 paintings to other military personnel as an expression of gratitude.

However, from 1946 until 1951 Mullaard remained in Ermelo which was too isolated from the Dutch art world. Due to financial hardship he was also unable to move back to Rotterdam in order to retake his place in the Rotterdam “art-scene”. Disheartened by the set-backs he experienced in the post-war economic environment between 1951 and 1953 Mullaard did not paint at all. He and his wife had to focus on survival, growing their own vegetables and selling a number of valuable belongings in order to have income. Some paintings were also exchanged for food and other necessities.

In 1953 in an effort to secure income, Mullaard decided to switch professions and started a documentary film company, named “Vision”. A few film documentaries were made and sold but Mullaard was very unhappy.

Between 1953 and 1958 only six paintings were made, however, by the end of 1958, unable to leave painting, Mullaard returned to art as his primary occupation. In 1959 he began to seriously paint again creating 7 paintings and selling two to the BPM Oil Company for its 50th Anniversary. A few years later, B.C. Tieman, the director of the local Rabo Bank (and admirer of Mullaard’s work) commissioned 6 paintings, one for each of Tieman’s sons.

Sadly, in 1964 Mullaard’s friend and mentor Jungmann passed away. This had a significant effect on Mullaard, he later commented that after Jungmann’s death he felt especially alone as an artist.

In 1966 Mullaard turned 65 and began receiving his state pension.  The next year he and his wife moved to Groningen, where as part of his retirement Mullaard became a member of the local fishing club. No longer focused on his career, Mullaard kept painting for the enjoyment of art though in 1969 an extensive review of Mullaard and his work appeared in the local newspaper.

In 1970 Mullaard again moved, this time to the center area of the country. In Bilthoven he found the home he would live in for the last twenty years of his life and also the inspiration for a number of paintings amongst the trees and forests of his new town. In 1973 and 1974 Mullaard took part in group expositions with glowing reviews of his works again printed in the local newspaper.

In 1980/1981 Mullaard’s last work was painted, his vision of the Rocky Mountains in Canada, created after his return from a vacation in 1979. His last newspaper interview was in September 1981 with a full-page report and photograph of Mullaard and his last painting printed in the arts section. Mullaard accepted this as a form of recognition and was proud of his artistic accomplishments in the end.

He left a collection of approximately 250 paintings and 25 sculptures, most of which are now in a private collection in Ontario, Canada.