He was known for his association with such successful productions as The Wizard of the Nile, The Princess Chic, Beside the Bonnie Brier Bush, Arizona, The Earl of Pawtucket, The Virginian, The Education of Mr. Pipp and The Heir to the Hoorah.

[9][10] In 1891 La Shelle left the dramatic desk of The Chicago Mail to join the English actor E. S. Willard as his business manager and advance man for an upcoming American tour.

[2][11] From 1892 to 1895 La Shelle served as general manager and director of the Bostonians, a theatrical troupe previously known as the Boston Ideal Opera Company.

[2] In 1895 La Shelle partnered with Arthur F. Clarke, the Bostonians’ former business manager and advance man, to back the Frank Daniels’ Comic Opera Company.

Their first production The Wizard of the Nile,[13] a comic operetta by Victor Herbert and Harry B. Smith, proved to be a huge success that earned its producers a fortune.

The Princess Chic premiered on New Year's Day 1900 at the Lafayette Square Opera House in Washington D. C. with Minnie Methot in the title role.

[24] La Shelle produced and shared the writing credits with Owen Wister on their successful 1903 stage adaptation of the author's popular novel The Virginian.

La Shelle suffered two accidents early in May 1905 while at his summer residence in Bellport, Long Island—a badly cut foot from a lawn mower and serious burns to his face while attempting to repair a hot water pipe.