After graduation, Alex joined the Bolshoi Ballet that same year and toured throughout Europe, Japan, Australia, New Zealand, Asia and the United States. He remained with the Bolshoi for four seasons where he was under the supervision of Bolshoi star, Boris Akimov.

Alex relocated to the United States. In New York, he took classes with Stanley Williams at the School of American Ballet and was introduced to Rudolf Nureyev who personally coached him for a production of The Nutcracker. Later, Alex worked with renowned choreographer, Lila York, in her production for Connecticut Ballet Theater.

In 1991, Alex was invited to the Vienna State Opera Ballet as a principal dancer. Over the course of the next few years, he performed all of the lead roles in the full-length classical ballets, as well as contemporary works by renowned choreographers John Nuemeier and John Cranko

Upon his return to New York City in 1995, Alex offered many roles as guest artist with various companies throughout North America. He joined the “Perry Dance Ensemble” under the direction of New York choreographer Igal Perry, the Artistic Director of Peridance Capezio Center

Alex partnered with New York City Ballet star Valentina Kozlova at the Joyce Theater in New York, as part of the “Daring Project” with original choreography by Margo Sappington.

Although trained in pure classical traditions, Alex also had the desire to explore the world of modern dance. In 1997, he joined Les Grands Ballets Canadiens in Montreal as a principal dancer and was immersed in works by such international choreographers as Jiri Kylian, Nacho Duate and James Kudelka.

In 1999, Boston Ballet offered Alex a position as principal. Under the direction of Anna Marie Holmes, he maintained lead roles in critically-acclaimed productions of La Bayadere, Don Quixote and Sleeping Beauty.  It was a unique opportunity to combine both worlds and enabled Alex to dance all of the beloved classics, works by Balanchine and modern choreographers.

In 2001, Alex worked closely with Peter Martins, Director of New York City Ballet, who created an original piece for him for a Gala at the Joyce Theatre.  The NY Times gave his performance an outstanding review.  That same year Alex led a production of Swan Lake by Bruce Marks for the Dallas Fort Worth Ballet.

In 2001-2005, Alex performed as a principal guest artist for Ballet San Jose Silicon Valley and continued his distinguished career internationally. Alex collaborated in productions of Miraculous Mandarin and Out of Africa by Danish choreographer Flemming Flindt.

Alex participated in many Gala performances such as the Vienna International Gala, Stars of American Ballet in Milan and the International Ballet Stars throughout Netherlands and Belgium. Alex also appeared on local television stations in Connecticut, Alabama, Massachusetts and California.

Retiring from an active career as a dancer, Alex focuses on teaching. In 2006 Alex was invited to the Miami City Ballet as a faculty member. He was in charge of classical ballet classes, pas de deux, and developed an open adult division.

In 2009, Alex was a guest ballet master with The Royal Ballet of Flanders, Stuttgart Ballet, The Royal Ballet School of Antwerp and worked internationally around the globe. He taught at Point Park College, Perry Dance NYC, Mills College, Ballet San Jose School, San Francisco City Ballet, Alonzo King’s Dance Center, and Joffrey Ballet NY.

In 2010-2011, Alex was a guest faculty with Boston Ballet and The Hartt School, University of Hartford. Alex also coached students for YAGP NY Finals and obtained his ABT® National Training certification (for all levels).

Alex co-founded Koltun Ballet Boston with Alexandra Koltun (his wife and former principal dancer).