"I don't profess to know anything about parenting, anything more than anybody else, [but] being a working mom is an incredible challenge, [and] it's an incredible gift," she told "Entertainment Tonight" on Wednesday at the amfAR New York Gala, an event that raises money for HIV/AIDS research.
Johansson, 32, is mom to 2-year-old Rose Dorothy.
"I think you always feel a little bit of guilt," the actress continued. "If you're at work, you feel like you're missing out on those special moments with your kid. If you're with your kid, you feel like you're not giving enough to your job. It's a balance."
"I have a lot of huge admiration for working moms. I'm barely, barely holding it together," Johansson admitted.
This was Johansson's first red carpet appearance since rumors circulated that she had split from her husband, French journalist Romain Dauriac. The actress may have fanned the flames by bringing her mother, Melanie Sloan, as her date.
"I really couldn't think of anybody else that I'd rather [have] with me here tonight," Johansson said. "[She's] been incredibly inspiring for me in many, many ways, but certainly as a young girl."
Johansson added, "She never shielded us from what was going on in the zeitgeist in culture. She always made us aware, you know, socially aware. She always encouraged us to be politically and socially active, so I couldn't imagine a better date tonight."