Rob Kardashian, his youngest child and only son, uploaded an old photo of him as a boy sitting on Robert's shoulders to Instagram late Monday.
Source: Rob Kardashian / Instagram
Source: Kim Kardashian West / Twitter
"To the best man I've ever known, happy birthday daddy," she tweeted. "I miss you! I miss you! I miss you!"
To the best man I've ever known, happy birthday daddy. I miss you! I miss you! I miss you! pic.twitter.com/h3c77eapkz— Khloé (@khloekardashian) February 22, 2016
Robert's eldest child Kourtney Kardashian also honored him on social media, tweeting, "Happy birthday to my favorite man in the world who taught me everything. I wish I could hug you. I love you Daddy."
Happy birthday to my favorite man in the world who taught me everything. I wish I could hug you. I love you Daddy. pic.twitter.com/9qqoo6Km4E— Kourtney Kardashian (@kourtneykardash) February 22, 2016
Robert died Sept. 30, 2009 from cancer. He was 59 and is survived by ex-wife Kris Jenner, now 60, and their four children: Kourney, 36, Kim, 35, Khloé, 31, and Rob, 28.
The businessman and attorney became a household name when he helped defend friend O.J. Simpson during his infamous 1994 murder trial. David Schwimmer plays Robert on FX's critically acclaimed miniseries about the case.
happy birthday. we miss you pic.twitter.com/SU0sjoY5U3— Kendall Jenner (@KendallJenner) February 22, 2016
Kris, 60, re-posted a home movie Robert shot of Khloé as a toddler.
Her daughter Kendall Jenner even posted a photo of Robert holding her and baby sister Kylie Jenner. "happy birthday. we miss you," she tweeted, adding a heart emoji.