For his first season, he figured out a way to do something new and basic: Every show will feature live music , including Pam Tanowitz’s exceptional collaboration with the pianist Simone Dinnerstein, “New Work for Goldberg Variations” and Ephrat Asherie Dance’s program, for which Ms. Asherie is teaming up with her brother, the jazz pianist Ehud Asherie.

And there’s lots of tap. In addition to Ms. Casel, the Joyce will host “And Still You Must Swing,” featuring the collective of Dormeshia, Derrick K. Grant and Jason Samuels Smith; and the choreographer Michelle Dorrance returns with her company and a premiere set to Duke Ellington’s interpretation of Tchaikovsky’s “Nutcracker Suite.”

The musicality of tap is a draw for Mr. Mattocks, who didn’t start out in dance. Growing up in Pennsylvania, he pursued classical music with a focus on piano, cello and voice. But in high school, he saw a performance of “Chicago” on Broadway and found himself obsessed with Bob Fosse. “I had this moment of not wanting to spend my whole life in isolation in a practice room,” he said. “I sort of broke up with classical music, and it was at a point where I was a senior in high school auditioning for conservatories. My parents were like, ‘What are you going to do?’”

He found the answer at Sarah Lawrence College, where during his freshman year he began studying dance with Viola Farber, the former Merce Cunningham dancer who headed the dance department. It was also at Sarah Lawrence, under the instruction of the historian and writer Rose Anne Thom, that he discovered the work of Mark Morris.

“I was certain that if I could get my way in the door with the Mark Morris Dance Group,” Mr. Mattocks said, “that he would fall in love with my humanity and put me in his dances.” When he learned the company was looking for a general manager, he applied for the position.

He saw the company and Mr. Morris as a version of Louisa May Alcott’s “Little Women” — if Mr. Morris and his company represented all of the March sisters, Mr. Mattocks was Laurie, the neighbor who falls in love with Jo but ends up with Amy. “I will marry into this family somehow,” was how Mr. Mattocks — laughing yet completely serious — put it.