But there's always been a lot more to Williams than just football. He's an educated man, one who has spiritual interests and has talked about wanting to spend his time learning more about science and medicine.
That's why, while Williams was still under contract for 2012, it wasn't a huge surprise to see him step away from the game today after 11 seasons in the NFL.
"The NFL has been an amazing page in this chapter of my life," Williams said in a statement. "I pray that all successive adventures offer me the same potential for growth, success and most importantly, fun. As for what's next, I am excited about all the opportunities ahead - continuing my education, running The Ricky Williams Foundation and whatever other opportunities present themselves.
"(Football) has been a big part of my life and blessed me with so many wonderful opportunities and the chance to connect with many people who have helped me grow and mature. I will miss the game, the camaraderie, my teammates and especially the emotions of a big victory. I love the game and leave it feeling fulfilled, proud, in great health and excited about the future."
Williams ends his career having come up just short of his first Super Bowl. The 34-year-old had 108 carries for 444 rushing yards and two touchdowns this season with the Ravens.
"I have to thank coach (John) Harbaugh and the Ravens organization for the opportunity they gave me this year," Williams said. "I had so much fun and really appreciated the chance to finish on such a great note."
With Williams by his side, Rice had a career-high 1,364 yards and a team-record 15 touchdowns this season, and he led the NFL in yards from scrimmage.
The two running backs weren't necessarily great friends, but they had a strong working relationship and Rice credits Williams for a lot of his success this season.
"I was a big fan of Ricky before we were teammates, but being around him this year is the best thing that happened to me in my NFL career," Rice said. "As a young player, you need to be around a guy who knows what he is doing, and Ricky was tremendous to learn from. The way he took care of his body and the way he prepared, he always showed that he is a true professional. This past season with him is a year I will never forget. I had the best year with him beside me, and that was no accident.
"I believe that Ricky Williams is a Hall of Famer. All that he has done in his career, he deserves that. I was honored to share the field with him when he went over 10,000 yards. What an amazing accomplishment, as he is one of the best. I will miss him, but I wish him and his family well."
The Ravens will save $1.5 million on the salary cap with Williams' retirement. I wouldn't be surprised to see them add an inexpensive free agent veteran to replace Williams, or they could turn to a younger player, such as Anthony Allen or Damien Berry.
"Ricky, in his time here, made a valuable and lasting contribution," Harbaugh said. "I especially enjoyed getting to know him as a person, and I have the utmost respect for him. He was great to be around and to work with every single day. We wish him all the best in his future endeavors."