Bishop Kelley Names Zach Postoak Head Varsity Baseball Coach

May 20, 2026

FOR IMMEDIATE RELEASE


Tulsa, OK - Bishop Kelley High School has officially named Zach Postoak as Head Varsity Baseball Coach following his service as Interim Head Coach during the 2025–2026 season.


Postoak joined the Bishop Kelley community during the 2024–2025 school year and has quickly become an important part of both the academic and athletic departments. He began as a full-time substitute teacher before transitioning midyear to teach computer literacy while also serving as an assistant coach for both the baseball and softball programs.


Prior to arriving at Bishop Kelley from Owasso Public Schools, Postoak taught and coached in Oklahoma at Berryhill Public Schools and Cushing Public Schools. During his career, he has served in both head baseball and assistant softball coaching roles, helping lead teams to district championships and postseason appearances. He also spent time coaching at Northwestern Oklahoma State University, where he earned a Bachelor of Science in Health and Sports Science.


During the 2025–2026 season, Postoak stepped into the Interim Head Baseball Coach role and helped guide the Comets to a runner-up finish at the OSSAA Class 5A State Baseball Championship.


“Zach has done an outstanding job leading our baseball program,” said Bishop Kelley Athletic Director Lance Parks. “This team competed at a very high level throughout the season, finished undefeated in district play, and made an outstanding run to the state championship game. We are excited to officially name Zach as our head varsity baseball coach and look forward to continuing to build on the momentum and success of this season.”


Postoak expressed gratitude for the opportunity to continue leading the program.


“I’m thankful for the opportunity to continue serving Bishop Kelley and leading this baseball program,” Postoak said. “This season gave our student-athletes the opportunity to grow, compete, and learn at an elite level together, and I’m excited to continue building on the foundation our players and coaching staff have established.”


In addition to serving as Head Varsity Baseball Coach, Postoak was recently named Head Softball Coach for the Comets softball program.


About Bishop Kelley Baseball
Bishop Kelley Baseball competes in OSSAA Class 5A and is committed to developing student-athletes who pursue excellence in competition, leadership, and character. The Comets program emphasizes discipline, teamwork, and representing Bishop Kelley with pride on and off the field.


About Bishop Kelley
Bishop Kelley High School is Oklahoma’s largest private high school and is considered a life-preparatory institution. It offers a faith-based education that fosters academic excellence, spiritual growth and personal development. The school features a rigorous curriculum, including more than 40 honors and AP courses across a wide range of disciplines. With an average ACT score of 28 and an average SAT score of 1260, Bishop Kelley graduates are well-prepared for college, with 90% attending four-year institutions. The Blessed Stanley Rother Academic Support Program provides individualized assistance to students with diverse learning needs.


Beyond the classroom, students can choose from more than 30 clubs and organizations, while athletes, academic bowl, and the speech and debate team compete in 20 OSSAA-sanctioned sports. The campus includes state-of-the-art facilities for academics, athletics, dining and the arts. Recent improvements were made possible through the successful completion of the $25 Million We Are BK capital campaign-funded entirely through private donors, not tuition dollars.

Bishop Kelley Welcomes Julia Dierker as Head Girls Golf Coach

May 20, 2026
FOR IMMEDIATE RELEASE Tulsa, Okla. - Bishop Kelley High School is pleased to announce the hiring of Julia Dierker as the school’s new Varsity Girls Golf Coach and a member of the Social Studies faculty. Dierker brings a strong combination of competitive golf experience, classroom leadership, and program development to Bishop Kelley. Most recently, she served as the Girls Varsity Golf Coach and English teacher at Broken Arrow Public Schools, where she revitalized the girls golf program and helped guide multiple student-athletes to collegiate golf opportunities. Under her leadership, the program earned back-to-back Frontier Valley Conference Runner-Up finishes, and at least one athlete committed to college golf each year. In addition to her coaching success, Dierker has experience teaching several subjects at the secondary level and will obtain her master’s degree through Northeastern State University at the end of this calendar year. She has also worked extensively in youth development and athletics programming through organizations such as First Tee-Tulsa. “Julia’s passion for mentoring young women, her competitive drive, and her commitment to helping students grow both academically and athletically make her an outstanding addition to Bishop Kelley,” said Lance Parks. “We are excited to welcome her to our community and look forward to the impact she will have on our students and golf program.” Dierker said she was drawn to Bishop Kelley because of the school’s strong academic standards, competitive culture, and mission-centered environment. “Coaching young women to lifelong improvement and success in the classroom and in sport is my passion,” Dierker said. “I admire the strong tradition of academic excellence, competitive achievement, and high standards that define Bishop Kelley, and I am excited for the opportunity to contribute to the continued success of the school and its students.” A former collegiate golfer herself, Dierker competed at both Coffeyville Community College and University of Arkansas–Fort Smith, earning Academic All-American honors and serving as team captain during her collegiate career. Dierker will begin her role at Bishop Kelley for the 2026–2027 school year. About Bishop Kelley Girls Golf The Bishop Kelley Girls Golf program has a strong tradition of competitive excellence, sportsmanship, and student-athlete development within the OSSAA. Comet golfers are challenged to grow both on and off the course through discipline, integrity, and a commitment to continual improvement. The program emphasizes individual growth while fostering a team culture rooted in accountability, encouragement, and respect for the game. Bishop Kelley Girls Golf strives to develop confident young women who pursue excellence in athletics, academics, leadership, and service while representing the mission and values of Bishop Kelley High School with pride. About Bishop Kelley Bishop Kelley High School is Oklahoma’s largest private high school and is considered a life-preparatory institution. It offers a faith-based education that fosters academic excellence, spiritual growth and personal development. The school features a rigorous curriculum, including more than 40 honors and AP courses across a wide range of disciplines. With an average ACT score of 28 and an average SAT score of 1260, Bishop Kelley graduates are well-prepared for college, with 90% attending four-year institutions. The Blessed Stanley Rother Academic Support Program provides individualized assistance to students with diverse learning needs. Beyond the classroom, students can choose from more than 30 clubs and organizations, while athletes, academic bowl, and the speech and debate teams compete in 20 OSSAA-sanctioned sports. The campus includes state-of-the-art facilities for academics, athletics, dining and the arts. Recent improvements were made possible through the successful completion of the $25 Million We Are BK capital campaign-funded entirely through private donors, not tuition dollars.

Bishop Kelley High School Names Alumna Hannah Gilliard Sipes ’04 as Director of Philanthropy

April 14, 2026
FOR IMMEDIATE RELEASE Tulsa, Okla. — Bishop Kelley High School is pleased to announce the appointment of alumna Hannah Gilliard Sipes ’04 as the next Director of Philanthropy. Sipes will begin her role on May 1, 2026, and will work alongside current Director of Philanthropy Doug Thomas through September, ensuring a thoughtful and seamless transition. A native Tulsan and proud Bishop Kelley graduate, Sipes returns to her alma mater with more than a decade of strategic leadership in nonprofit fundraising and a deep commitment to mission-driven work. She earned her degree in Business Management from Oklahoma State University and has built a strong reputation across Tulsa for cultivating meaningful relationships and advancing philanthropic impact. “As a Bishop Kelley alumna, Hannah understands firsthand the lifelong value of a Bishop Kelley Catholic education,” said Sister Mary Hanah Doak, RSM, President of Bishop Kelley High School. “Her professional experience, combined with her heart for this community, makes her uniquely positioned to lead our philanthropic efforts in service of students into the future. We are thrilled to welcome her home.” During her time as a student at Bishop Kelley, Sipes was actively involved in theater, one-act plays, improvisation, and speech and debate. These formative experiences sparked her appreciation for communication, creativity, and community engagement. Most recently, Sipes served as Associate Director of Advancement for Development at Cascia Hall Preparatory School. She previously held leadership roles with Global Gardens and the American Heart Association, where she focused on corporate partnerships and philanthropic growth. She is an active member of the Association of Fundraising Professionals. Sipes will succeed Doug Thomas, who will retire in September 2026 after 14 years of extraordinary service to Bishop Kelley. The five-month overlap between Thomas and Sipes is a rare and meaningful opportunity that reflects Bishop Kelley’s commitment to continuity, stewardship, and long-term success. Together, they will work closely to ensure a smooth transition and continued momentum in advancing the school’s philanthropic priorities. “I am honored and excited to return to Bishop Kelley in this role,” said Sipes. “This community played a significant role in shaping who I am, and I look forward to building on the strong foundation already in place to support future generations of students.” Sipes lives in Sand Springs with her husband, James, an Army veteran, and their two daughters, who attend Marquette Catholic School. The family are parishioners at Christ the King Catholic Church. Outside of work, she enjoys spending time with her family-cheering on her daughters in their activities, and exploring national parks together. With deep roots in the Bishop Kelley community and a clear vision for the future, Sipes will lead the school’s philanthropic efforts in support of its mission to prepare students’ hearts and minds for a purposeful life. Bishop Kelley Mission Statement Bishop Kelley is a Catholic diocesan high school, inspired by St. John Baptist De La Salle, that carries on the teaching ministry of Jesus Christ by preparing students’ hearts and minds for a purposeful life. More About Bishop Kelley Bishop Kelley High School is Oklahoma’s largest private high school and is considered a life-preparatory institution. It offers a faith-based education that fosters academic excellence, spiritual growth and personal development. The school features a rigorous curriculum, including more than 40 honors and AP courses across a wide range of disciplines. With an average ACT score of 28 and an average SAT score of 1260, Bishop Kelley graduates are well-prepared for college, with 90% attending four-year institutions. The Blessed Stanley Rother Academic Support Program provides individualized assistance to students with diverse learning needs. Beyond the classroom, students can choose from more than 30 clubs and organizations, while athletes, academic bowl, and the speech and debate team compete in 20 OSSAA-sanctioned sports. The campus includes state-of-the-art facilities for academics, athletics, dining and the arts. Recent improvements were made possible through the successful completion of the $25 Million We Are BK capital campaign-funded entirely through private donors, not tuition dollars.