Guillermina's career as a folk artist began later than her sister Josefina's. The first Aguilar sibling to marry, she and her husband, Leopoldo (whose younger brother later became Josefina's husband), tried their hands at everything they could think of to establish their independence. Guillermina continued to make and sell apaxtles, (utilitarian clay bowls) as she had done in her mother's home. The young couple would hustle to Oaxaca before dawn to buy baked rolls not available in Ocotlán, returning at 6 AM to sell them. At one point, Guillermina also cooked in a tiny restaurant, at another, she sold fruit. But by the time of her mother's death in 1968, with four children to support, she knew that kind of hustling would never be enough, given the poverty of the Oaxacan countryside. "I said to my husband . 'Look, I am going to work in clay'. I knew that if I didn't I wouldn't survive."
She began simply, making the traditional braseros, or incense burners, favored in her community for use on the day of the Dead, and ceramic bells with animal heads that her mother had designed at the suggestion of a Oaxacan folk art enthusiast. The braseros still hold a special place in her heart, connecting her, in their creation, to her mother and to her religious faith.
Quietly and steadily her reputation developed. One day in the early 1970's, a man from the nearby village of san Martën who had just been appointed Oaxaca's representative for FONART, the government agency supporting folk crafts, came to see her. It was an important moment: "You're Guillermina; well, we need work. But I don't want the things you are making. What I want are skeletons. Here's money and you pay it back with skeletons". He wanted dressed skeleton figures and colorful candlesticks in the shape of skulls, populaf Mexican motifs, especially for the Day of the Dead. She could not believe her good fortune, but at the same time, doubted that she was up to the task. Her husband convinced her she was. The ceramic figures she began producing very quickly revealed her special abilities.
With her confidence fortified, her imagination unleashed, and her talent established, Guillermina's career as a prominent ceramist took off. An invitation to meet the Queen of Spain soon followed. Another ivitation came immediately after that to exhibit in the United States. The opportunities, awards, and honors have continued ever since. Yet in her devout and self-effacing manner, Guillermina will not ackowledge her own part in success: "Thank God, with God's strength, we came out ahead."
Guillermina's family is central to all her efforts. When the land needs to be worked, her five sons head out to the fields early with her husband, making sure to return by middday so they still have energy left to work in clay. All of the children also work in the clay to help complete orders; each specializing in certain types of figures. The cooking is also shared by all so that all have time to work the clay without interruption. Despite the continuing economic struggles, working with clay offers Guillermina a deeply emotional experience. "I think the more love one puts into the clay, the more beautiful it comes out. If you get angry, it doesn't come out well. The piece comes out crooked, it comes out badly." It is the intensity with which she feels both joy and sadness as she works that affects her most deeply: :The happiness comes from that moment you pour your heart into what you are creating. The sadness comes from then having to part with what you have just put so much love into." She looks wistful for a moment, then smiles: "To think, from that sadness and that joy, one earns a living!"