"Whenever she needed me, I was ready to serve," Asner told ET's Brendon Geoffrion. The two worked together on The Mary Tyler Moore Show for seven years, which led to "a tight relationship but one with a great distance between it."
Moore died on Wednesday from cardiopulmonary arrest after she had contracted pneumonia. The groundbreaking actress was 80.
"She was perky," recalled Asner, who said it was his daughter, Liza, who informed him of Moore's death. "Everybody likes a perky person and Mary was the champion of perkiness. She's honest, she doesn't take any bulls**t and she's a fairly straight shooter. She wasn't hard hitting like Lucille Ball, but she still had that ability to accept or dismiss and I value her for that."
Asner, who admits he developed a crush on Moore, also remembered the first time they met.
"My first impression of Mary -- beautiful," he said. "To be expected and beautiful women always scared me. I thought, 'Aha, beauty and yet she's probably got two bowie knives tucked in the back of her belt.' So, I waited for the knockout punches. They never came."
After working together for six years, Asner and Moore's characters on The Mary Tyler Moore Show shared their very first kiss -- a moment Asner hasn't forgotten. "I was nervous about controlling myself," he recalled.
"I had to do it for the TV audience, so I let her dictate the conditions for the kiss," he continued, adding that she was a very good kisser.
Over the years, the Kansas City native, who went on to star in his own spinoff, Lou Grant, after The Mary Tyler Moore Show wrapped its seventh season, says Moore "was always there to support me, I never felt discouragement."
"She was an icon," Asner added. "She was always very appropriate and prepared. If she believed in you, she went all the way."