---
id: "d2f5731d-cc89-4cc6-8e99-088d1a593af0"
type: "Person"
name: "Cal Henderson"
slug: "cal-henderson"
canonical: "https://groundingwiki.com/en/people/cal-henderson/"
markdown: "https://groundingwiki.com/en/people/cal-henderson/index.md"
language: en
same_as:
  - "https://wikidata.org/wiki/Q5018144"
---

# Cal Henderson

Cal Henderson is a software engineer and technology executive who co-founded Slack and served as its chief technology officer until 2024. [1] [2] [3]

The markers cite the evidence for the underlying claims. They do not mean one source contains this full sentence.

## Core facts

- **Entity type:** Person

- **Date of birth:** 17 January 1981 — [4] structured public data, checked 22 Sept 2026

- **Occupations:** Software engineer and technology executive — [2] first-party, checked 23 Sept 2026

- **Official profile or website:** [iamcal.com](https://www.iamcal.com/) — [5] first-party, checked 22 Sept 2026

## Who is Cal Henderson?

While at Slack, Henderson was one of its founders and served as chief technology officer. He stepped down from the CTO role in January 2024 and left Slack in March 2024. — [1] regulatory filing, checked 23 Sept 2026; [3] independent, checked 23 Sept 2026

## History

- **iamcal\_site:** Personal site iamcal.com has published since June 2000 — [6] first-party, checked 23 Sept 2026

- **slack\_cto\_departure:** Stepped down in January 2024; remained at Slack until March 1, 2024 — [3] independent, checked 23 Sept 2026

- **slack\_founder:** Co-founder of Slack — [1] regulatory filing, checked 23 Sept 2026

- **slack\_merger:** Signed a founder voting and support agreement for Salesforce’s Slack merger — [1] regulatory filing, checked 23 Sept 2026

## Leadership

- **Slack Cto:** Chief technology officer of Slack until January 2024 — [3] independent, checked 23 Sept 2026

## Relationships

- **founded:** Slack — [1] regulatory filing, checked 23 Sept 2026

## Sources
1. [Slack/Salesforce merger proxy statement](https://sec.gov/Archives/edgar/data/1764925/000119312521022117/d13689ddefm14a.htm)
   - Publisher: U.S. Securities and Exchange Commission
   - Type: regulatory filing
   - Checked: 23 Sept 2026
   - Evidence:
     - Definition: "Slack’s SEC merger proxy identifies Henderson among the founders and names him as CTO in the merger arrangements."
     - Who is Cal Henderson?: "The SEC identifies Henderson among the founders and names him as CTO in the merger arrangements."
     - slack\_founder: "Slack’s SEC merger proxy explicitly lists Henderson among Slack’s founders."
     - slack\_merger: "The SEC proxy names Henderson among Slack’s founders who signed the voting and support agreement."
     - founded: "Slack’s SEC merger proxy identifies Henderson among its founders."
2. [The five-day workweek has left the building](https://slack.com/intl/es-es/blog/transformation/the-five-day-workweek-has-left-the-building)
   - Publisher: Slack
   - Type: first-party
   - Checked: 23 Sept 2026
   - Evidence:
     - Definition: "Slack identifies Henderson as its co-founder and chief technology officer; Fortune reports his departure from the CTO role in 2024."
     - Occupations: "Slack identifies Henderson as its CTO and discusses his engineering leadership."
3. [Slack CTO Cal Henderson is out](https://fortune.com/2024/01/12/slack-cto-cal-henderson-out-replaced-salesforce-cofounder-parker-harris)
   - Publisher: Fortune
   - Type: independent
   - Checked: 23 Sept 2026
   - Evidence:
     - Definition: "Fortune reports Henderson’s co-founder and CTO roles and his departure from Slack in 2024."
     - Who is Cal Henderson?: "Fortune reports the CTO change was effective January 2024 and that Henderson remained until March 1."
     - slack\_cto\_departure: "Fortune reports the CTO change was effective immediately on January 12 and that Henderson would remain until March 1."
     - Slack Cto: "Fortune reports that Henderson stepped down as Slack CTO effective January 2024."
4. [Cal Henderson — Wikidata](https://wikidata.org/wiki/Q5018144)
   - Publisher: Wikidata
   - Type: structured public data
   - Checked: 22 Sept 2026
   - Evidence:
     - Date of birth: "Wikidata P569 dates the birth of Cal Henderson."
5. [iamcal.com](https://iamcal.com/)
   - Publisher: iamcal.com
   - Type: first-party
   - Checked: 22 Sept 2026
6. [About iamcal.com](https://iamcal.com/about/about)
   - Publisher: Cal Henderson
   - Type: first-party
   - Checked: 23 Sept 2026
   - Evidence:
     - iamcal\_site: "Henderson’s About page says he has maintained the site’s linklog and weblog regularly since June 2000."

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