The week after Craig Biesecker gives his final performance with the Mark Morris Dance Group—in the much-anticipated return of the luminous and masterful L’Allegro, il Penseroso ed il Moderato—he will start classes at City College for a masters degree in landscape architecture. Bradon McDonald’s transition from dancer to student will be even more abrupt. After performing in the company’s Oct. 3 matinee in Berkeley, Calif., he will catch a flight to Los Angeles and show up the next morning for orientation at Fashion Institute of Design and Merchandising.

Both Biesecker, 36, and McDonald, 35, have been confronting the difficult and unavoidable issues that every dancer faces at some point—how long to continue performing; whether to leave the stage while still at one’s peak; or adapt to different repertory as one’s body matures. If they are fortunate, dancers can choose to stop performing on their own terms rather than because of a dire injury. These two Mark Morris company mainstays have decided to leave the stage while still in peak form, and have discovered new career paths that offer exciting possibilities.

“Eventually, dance performance of this type has to end on the early side of life,” McDonald says in between MMDG rehearsals. “What I’ve loved about this career is dancing Mark’s work, which is amazing. I’m not really interested in doing other kinds of performing full-time. I really want to start a new career that will last me the rest of my life, and do it while I’m young enough—and dumb enough—to start another completely impractical adventure! I could easily dance another five to seven years without much problem, but going back to school at that point, and then taking time to build a career, seems scarier to me than doing it now—although it’s still a petrifying prospect to leave dancing.”

The 1997 Juilliard graduate, who danced with the Limón Dance Company before joining MMDG in 2000, has been a dynamic, blazing presence in the Morris repertory over the past decade. But throughout his very busy dance career, he has also found time for design and fashion projects. This longstanding interest goes back to his high school in upstate New York, which offered an unusually strong fine arts program. Once he focused on becoming a professional dancer, he still found many creative outlets—he started designing and making bags while at Juilliard, and they became so popular that the annual fall sale of his creations would quickly sell out. “I would travel with my sewing machine in my suitcase and set up shop on tour. Every hotel room became my studio for three days,” McDonald recalls.

Biesecker, who joined MMDG in 2003, has a college degree in music education, but once he committed to a dance career, “that was the end of that chapter,” he says. His thoughtful, gentle presence and elegantly focused dancing have graced numerous Morris works, and he took over the role of Aeneas in the choreographer’s powerful production of Dido and Aeneas. Like McDonald, he senses that now is the ideal time to make his next move. “I think I could go for a few more years, but I don’t know if I want to push that envelope that far.” Meetings with representatives of Career Transition for Dancers helped him identify and research areas of interest. “I had some ideas, and they had great suggestions. They’re a great help. I have a scholarship from CTFD which has been great for school.” Once he identified landscape architecture as his area of study, he was heartened to discover that the director of CCNY’s masters program is a former dancer herself.

Both men cite many highlights from their MMDG tenures. For Biesecker, his inaugural performance, on tour in Sydney as an understudy and not yet a company member, required him to perform several works on opening night on three hours’ notice, remains a “thrilling” memory.

“I loved Mark’s work. It was what I aspired to do. For me, it was the ultimate job. I got to travel the world, perform great works, have great experiences with musicians, and be in the room with Mark making up dances.”

McDonald recalls tacking the demanding, dramatic double role of Dido/The Sorceress, originated by Morris himself, as a particular highlight. It was when he had seen Morris performing in that work that “it all clicked. I felt I was in the right place at right time, professionally, for the first time, and it was wonderful.” Other favorite memories are a tour of Japan with Yo-Yo Ma, and the company’s Tanglewood Music Festival residencies. “L’Allegro is such an amazing show; that was my first performance with the company, in London,” he notes. Fittingly it will be the work in which New York audiences say farewell to him next week.

L’Allegro, il Penseroso ed il Moderato

Aug. 5-7, David H Koch Theater, 20 Lincoln Center Plaza (at W. 63rd St.), 212-721-6500; 7:30, $35 and up.