The comedian and television and radio personality - who delivered the eulogy at the memorial service at the Temple Emanu-El in Manhattan, New York - is said to have struggled to fight back tears as he stood in front of the legendary comedienne's friends and family.
TV host Hoda Kotb told USA Today: ''He was such a surprise when he got up and spoke. He was teary.''
The 50-year-old news anchor also revealed that she felt the service ''felt like a Broadway show with tons of humour, lots of tears and ended with a standing ovation'' because of performances from actors Hugh Jackman and Audra McDonald, and Howard's speech.
Meanwhile, Joan's 'Fashion Police!' co-host Kelly Osbourne has revealed she was so exhausted following the emotional service that when she lied down to take a short nap she didn't wake until five hours later.
She wrote on her Twitter page: ''Laid down 4 what I thought was a quick nap. Woke up 5 hours later in a pitch black room with no idea where I was #DeepSleep #TiredTears (sic).''
The 29-year-old beauty also confessed that learning of her close friend's death had resulted in her experiencing ''one of the worst days'' of her life, but insisted she was trying to stay strong for Joan's daughter Melissa.
She wrote: ''Thank you 4 all your love & support it goes without saying that this is 1 of the worst days of my life! We all must stay strong 4 @MelRivers.''
Joan passed away last Thursday (04.09.14) after being place in a medically-induced coma at Mount Sinai hospital in New York after she suffered a cardiac and respiratory arrest during a routine operation on her vocal cords.