Keegan's notable Broadway credits outside of The Phantom of the Opera include roles in Sweeney Todd: The Demon Barber of Fleet Street, Camelot, Cyrano: The Musical, and Pippin.[3]
In 1999, Keegan was promoted from his usual role in The Phantom of the Opera on Broadway as Monsieur Reyer to principal Phantom as he replaced Hugh Panaro for a month before Howard McGillin took over. This made Keegan the twelfth principal Phantom on Broadway.[4][1][5][2]
Also in 1999, Keegan started a 4-year stint in the 3rd US national tour as The Phantom before joining the Las Vegas company in 2006.[1][2]
In 2010, Keegan played Monsieur André in the Broadway company of Phantom. He stayed with the Broadway company on and off for 10 years in many roles, while also being a Phantom understudy. He was a permanent member of the Broadway company as the Jeweller (Il Muto) from the first performance after the Covid-19 shutdown, October 22, 2021, until the final performance on April 16th, 2023. During the show's last two weeks, Keegan alternated in the title role with Jeremy Stolle and Laird Mackintosh while principal Phantom Ben Crawford was sick.[3][1] His final performance as the Phantom was the April 15th matinee, making him the penultimate actor to play the role in the original Broadway production.