Mater Dei has a variety of fantastic teachers who show deep care and commitment to their students. Students are fortunate to have these caring mentors throughout their high school career. Math Teacher Sean Lieblang is one of these well loved instructors known to set his students up for success and is both an encouraging and charismatic mentor. 

Lieblang is one of the Algebra 2/Trigonometry and Algebra 2/Trigonometry Honors teachers for the current 2024-2025 school year. He began his career at Mater Dei in 1985. This year marks a major milestone for him, being his 40th year of teaching at the school. During his time at Mater Dei, he has taught every math class offered except for geometry and calculus. 

Lieblang initially earned his Bachelor’s Degree in Science from the University of Southern California followed by a Masters in Science from Northern Arizona University, and finally his Teaching Credential with an emphasis in Math from the University of California, Irvine. 

After college, Lieblang didn’t go into education right away. It wasn’t until teaching religion at his local parish that he developed a passion for teaching. At the time, he also had a number of  friends who taught and would share stories of their experiences which contributed towards his decision to pursue teaching. 

“A long time ago, I used to work for an oil company, which I liked, but then I started teaching religion at my local parish,” Lieblang said. “I had some friends that taught [at Mater Dei], so I would talk to them about it. I really couldn’t see myself [working at that other job] for the rest of my life, even though I liked it.”   

Lieblang values the importance of a Catholic education. As a youth, he attended St. Michael’s Prep, a small all-boys high school in El Toro. The school was managed by the Norbertine Priests who guided Lieblang in his strong Catholic foundation and continued to foster his love for the religion. 

“I don’t think I’d teach at any place other than a Catholic school,” Lieblang said. “Where else can you teach that God is sitting in a building a few doors down?”

40 years ago when he began his teaching journey, Lieblang had to decide what subject he would want to teach. He was torn between instructing in earth science or mathematics due to his college degree. He explains his rationale for choosing to teach math.

“My degree is not [in] math, [it is] in geology,” Lieblang said. “There were two things I could do: math [or] earth science. I love geology too much to try and teach it. If someone doesn’t like math, I could live with it. If someone didn’t like geology, I don’t think I could handle it.”

Lieblang has many favorite aspects of teaching, but he appreciates collaborating with his peers the most. He especially enjoys working with the other teachers. The faculty and students at Mater Dei contribute to the supportive and positive community, allowing him to enjoy working with his coworkers. 

“I’d have to say the people [are my favorite part], believe it or not,” Lieblang said. “I know this isn’t really teaching , but the people I work with, the other [teachers] in the Math Department, they’re just great.”

In Lieblang’s class students receive opportunities to collaborate with their peers on a regular basis, learn how to solve complicated problems, and apply the knowledge they learn in class. His students collectively agree that his class is a supportive environment, filled with memorable moments. Senior Oliver Yang, one of Mr. Lieblang’s former students, enjoyed the class and has fond memories from the course. 

“Him screaming about PEMDAS and making us scream [it] back [was my favorite memory from the class],” Yang said. “I liked collaborating with the person behind [me too].”

Lieblang ensures that students will not just understand but will always remember the material that he teaches. Whether it is partner work, recitation, or practice problems, he makes sure to equip his students with tools which they can apply to their lives on a daily basis. 

“I want to teach them ideas, not just specific problems, so that they can solve anything,” Lieblang said. 

One of his current students, freshman Sammie Riviera, thoroughly enjoys the class. She communicates her appreciation for the class and Mr. Lieblang’s teaching style. 

“Yes, [I have learned important skills so far in the class] because he makes it so we’re able to know exactly what to do for each problem,” Riviera said. “[The class] is unique because I’ve never had such rigorous teaching in math. Now that there’s more structure [which] I like more, it’s honestly helped me try harder [and be more successful]. [His teaching style] is effective. He’s very surprising. He’ll call on you, no matter what, and it keeps you on your toes, so you’re able to not crack under pressure.” 

Although his class might seem difficult at first, Lieblang purposefully makes the practice problems harder to make sure his students understand the basic concepts. When the test rolls around, students are able to solve straightforward problems with ease. It is so much more fulfilling when students do well on his tests. Junior Sophia Shrader was in Lieblang’s class last year, and touches on her overall love for the class. 

“[The most memorable moment was] doing well in my final,” Shrader said. “[His class was] difficult, [but] he’s a good teacher.” 

Lieblang has many notable traditions that occur in every class and during every year. Whether it is remembering the difference between expressions and equations, or winning a tie for earning the highest score on one of his tests, it keeps students interested and excited during every lesson. He has a variety of teaching philosophies he tries to abide by. He works to teach his students concepts and strategies that they can apply to any problem. Although math is very important, he believes that honesty and ownership are crucial principles that should be taught. 

“[The] most important thing I hope I would instill in students is to take responsibility for their own actions,” Lieblang said. 

Lieblang’s class is a course you can definitely look back on with fond memories. If you have not been his student yet, anticipate an energetic year filled with fun math problems. Many students agree, he has changed countless lives and been a supportive mentor to all. 

“Thank you for everything,” Yang said. “We appreciate [all you do for the school]!”