Citing the physical demands of the sport and a lost desire to keep fighting, Andre Ward announced his retirement Thursday in a statement posted on his website. 

The 33-year-old Ward (32-0, 16 KOs), the last American male to win an Olympic gold medal in boxing, is fresh off arguably the two biggest victories of his career when he moved up in weight to defeat then-unbeaten and pound-for-pound ranked Sergey Kovalev. 

Upon his knockout of Kovalev via body shot in June, Ward rose to the top of most pound-for-pound lists as the best boxer in the world. 

"To the sport of boxing -- I love you," Ward said. "You've been by my side since I was 10-years-old. You've taught me so much. You've humbled me. You've promoted me. I've sacrificed a lot for you, but you've given me more than I ever thought possible. You gave me a platform, made me a champion and helped me provide for my family. I am forever grateful to you. 

"You and I will always be synonymous, connected at the hip. Thank you for all the wonderful people I've come in contact with because of you. I've made friends for life. As I walk away from the sport of boxing today, I leave at the top of your glorious mountain, which was always my vision and my dream. I did it. We did it."

Ward, a native of Oakland, California, has grown into a quality television analyst in recent years and has never been one to worry about criticism while taking extended breaks from the ring to rest from injury or sort out disputes with his promoters. He has largely navigated his career on his own terms, and he is now the rare boxer to walk away before his prime has been compromised.

"From the bottom of my heart, thank you to everyone who has played a part in my journey," Ward said. "You know who you are. I could not have done this without you. I want to be clear -- I am leaving because my body can no longer put up with the rigors of the sport and therefore my desire to fight is no longer there.

"If I cannot give my family, my team, and the fans everything that I have, then I should no longer be fighting. Above all, I give God the glory, for allowing me to do what I've done, for as long as I have."  

Ward, a two-division champion who made his pro debut in 2004, exits the sport with an unblemished record as one of the best boxers of his era.

"Andre Ward ends his boxing career as he only knew how to live it -- as a champion at the top," said Peter Nelson, executive vice president of HBO Sports. "To watch Ward was to marvel at constant mastery of craft in the ring, to say nothing of his being the consummate role model outside it. The Hall of Fame will be lucky to have him.

"We wish Andre and his family much success and happiness as he explores new opportunities, including with our own HBO family as one of the expert analysts on our broadcast team. It was a privilege for HBO to serve as the television platform for many of his landmark achievements in the sport he loves."

Immediately after his second victory over Kovalev, Ward teased a move up to heavyweight for the right bout that never came to fruition. He also leaves behind a trio of light heavyweight titles and a marketable fight against lineal champion Adonis Stevenson that was never consummated.