Parker Lessmann began as the associate director of Rockwall High School choir in 2019, where he directs the school's all female contemporary a cappella ensemble, Sting. The 2021 ICHSA national finalists released their CARA-nominated albums Coronation (2021) and Rule The World (2023) and are consistently the top-performing all-treble group in the nation. He has served as music director for Little Shop of Horrors, Spring Awakening, Chicago, Anastasia, The 25th Putnam County Spelling Bee, The Phantom of the Opera, and Sister Act.

Prior to RHS, he served as associate choral director at McKinney High School from 2017-2019 following his time directing at the Austin Academy for Excellence in Garland ISD. Under his direction, his choirs have exclusively earned Sweepstakes ratings at UIL Concert & Sightreading, and superior ratings at multiple choral festivals, including Best in Class.

Mr. Lessmann is a graduate of Texas Christian University, where he earned his Bachelor of Music Education, and Texas A&M University-Commerce, where he earned his Masters of Education. During his time at TCU, he participated in various ensembles, including the TCU Concert Chorale, University Singers, Jazz Ensemble, and the Frog Corps men's chorus. He has previously served as a vocalist in the Dallas Bach Society and the Verdigris Ensemble. Currently, he serves as a choral section leader at St. Andrew United Methodist Church of Plano, and is a member of the Texas Choral Directors Association and Texas Music Educators Association.