Student Council is to be a representative body of students providing the administration with input, insight, and taking an active role in the management of student activities. All students have an opportunity to run for these student positions.

The Limelighters is a choir that competes in Varsity Vocals' International Championship of High School A Cappella (ICHSA). Students learn a "set" for the competition including challenging pieces that are performed with choreography. In addition to A Cappella pieces, the Limelighters also perform classical and contemporary pieces. An audition is required to be part of this ensemble. Gold Standard is another vocal ensemble at Lehman that is open to all students, no audition required. Both ensembles are co-curricular and have concerts during the school year.

This selective year-long program offers high school students a unique opportunity to blend personal growth with service to others. As a co-curricular, this program is taught in the classroom and includes extra-curricular activities. 

There are multiple instrumental ensembles at Lehman including Marching Band, Concert Band, and Jazz Band. With so many opportunities, anyone who wants to play an instrument will be able to find an ensemble that fits them. 

Science Olympiad tournaments are academic interscholastic competitions, which consist of a series of 23 individual and team events in all areas of science. The competitions are in March and April, and this activity is open to all interested students. Lehman competes at the regional, state, and national levels.

Membership is open to all students and teachers who have an interest in learning about investments. Students work with a broker and purchase shares of stock, then track them for the year, and at the end sell the shares. Money is returned at the end of the school year according to the success of the investment. Each student and teacher who participates is expected to invest $50.00.

Sketch Club meets bi-weekly to create art based on prompts. Guest artists are regularly brought in to share their techniques with members.

Students participate in an inter‑county school quiz competition normally held in the fall.

The Mock Trial Program is an academic competition designed to foster a better understanding of the American legal system and to encourage development of analytical and communication skills. The program is open to all students in grades 9-12.